I Am a Leader, I Am a Mother, I Can Do This! The Moderated Mediation of Psychological Capital, Work–Family Conﬂict, and Having Children on Well-Being of Women Leaders

: Gender equality is one of the Sustainable Development Goals. Management is one of the jobs that more clearly needs a gender perspective. Women leaders have found a way around the labyrinth to get to the top, which might have developed their personal resources such as psychological capital. Women leaders experience an inter-role conﬂict when work and family demands are mutually incompatible, a ﬀ ecting negatively their well-being. This study aims to analyze the mediation role that work–family and family–work conﬂict plays between psychological capital and well-being (engagement and burnout) when moderated by the number of children. In total, 202 Spanish women leaders participated in the study. Results of the mediated moderation model using Model 14 of the macro PROCESS for SPSS software show that psychological capital bu ﬀ ers the negative e ﬀ ects that experiencing work–family conﬂict has on well-being when having children. The well-being of women leaders is not a ﬀ ected when dealing with family interfering work conﬂict and having children. As such, women leaders who have children rely on their psychological capital to successfully manage the family demands a ﬀ ecting their work and to reduce the negative e ﬀ ect of work–family conﬂict on their well-being. Theoretical and practical implications are discussed from the psychology of a sustainability perspective.


Introduction
The 2030 Agenda for Sustainable Development adopted by the United Nations (UN) General Assembly incorporated, as a part of the 17 Sustainable Development Goals (SDGs), actions promoting worthy working conditions for a healthy workplace environment in order to ensure the reduction of economic and social inequalities. In this regard, SDGs recognize not only environmental or socio-economic concerns, but also the well-being of human and occupational health [1], considering that work plays a key role in citizens' life [2]. In this respect, at least four of the UN SDGs foster a gender perspective on the working conditions and occupational health, promoting gender equality and encouraging decent work, in the view that it increases economic growth [3].
Healthy organizations aim to promote workers' well-being through practices, culture, and work environments that lead to successful businesses and employees' health, thus becoming a driver for their own sustainability, growth, and productivity [2] on a demanding natural environment and the globalized technological world [2,4]. Regarding a sustainable life-work relationship, a new paradigm, named as the psychology of sustainability and sustainable development [5], considers that healthy organizations have to foster well-being through optimizing the use of personal resources (e.g., PsyCap) [6,7] and regenerating them [8] in a culturally diverse world [5,9]. The psychology of sustainability and sustainable development suggests a multilevel intervention approach into the organizations, where new awareness "is needed through the balance between 'me,' 'we,' 'organization,' 'people,' and 'the world' " [5] (p. 3), helping the connections between the personal, teamwork, and organizational narratives [5,[10][11][12]. According to these interrelations, work-life balance represents one of the backbones of psychology of sustainability, sustainable development and healthy organizations. Nevertheless, from a gender-aware perspective and due to the sexual division of work, women still have a predominant role in the private scope [13], which causes a conflict between organizational and personal narratives. Likewise, there is no sustainable development without gender equality. The United Nations Environment Programme (UNEP) believes that women suffer a greater impact of unsustainable behavior in all its dimensions. Since this impact has been extensively studied from an environment view, this article comes to fill a research gap that relates the psychology of sustainability with a gender perspective.
One of the jobs in which the need for a gender perspective and working conditions is more clearly drawn is management. Women leaders have to deal with a unique set of demands in comparison with their male counterparts. According to the role incongruity model, [14] the exertion of leadership is a conflicting role for women due to the gendered prescription of the characteristics and behaviors typically expected from leaders to men. Consequently, women in organizations are confronted by structural barriers [15] that make up the labyrinth of twists and turns of the routes to get to the top [16] that the women leaders have found all the way around them. Additionally, women are still doing the lion's share of domestic chores and child care despite their presence in the labor market [17]. Women leaders have a second shift at home [18], a demand caused by the gendered allocation of the household and its responsibilities to women. Cheung and Halpern [19] point out that studies of work-family conflict (WFC) and family-work conflict (FWC) seldom include leaders at the top with important family care responsibilities nor particularly women leaders. They also affirm that only half of the women leaders who are at the top of organizations have children because they are confronted by a double standard. For men, because of their roles as breadwinners, having children is a sign of their responsibility and stability, notwithstanding for women the same situation undermines their working conditions (e.g., salary, promotions).
It is plausible to suggest that women leaders may have developed personal resources from coping with the distinctive demands of both their family and work roles. It seems that women in management positions increase the overall subjective well-being as men do; besides, these women are more stress-resistant to the interferences between work and private life than their male counterparts [20]. Women leaders with children who have successfully combined their family and working roles possess personal characteristics and develop strategies that enable them to overcome the conflicts between their work and family roles, finding higher job satisfaction, and psychological well-being [19]. These authors highlight that women leaders have a pattern of a continuous process of self-empowerment and self-monitoring in taking on exigent responsibilities. The underlying set of personal resources of these processes could be Psychological Capital (PsyCap), which provides these women with the energy, motivation, and persistence to pursue their goals. PsyCap is a positive personal resource that consists of four personality strengths: hope, self-efficacy, resilience, and optimism [21]. The components of PsyCap are conceptually different but share a common variance [21] and can be classified as gain-oriented resources (e.g., self-efficacy, hope, and optimism) that build the motivation and energy required for goal achievement; and as loss-oriented resources (e.g., resilience), which act as a protection mechanism against a potential resource loss [22].
Despite the importance of PsyCap in buffering the effects of WFC in women leaders, to date no study has focused on it. Therefore, to fill this gap, the objective of this study is to analyse the mediation role that WFC and FWC plays between PsyCap and well-being (work-engagement and burnout) when moderated by the number of children, considering a gender perspective. By so, this study expands the literature about the impact of women leaders' personal resources on managing the conflict between their work and family roles and on their well-being. More specifically, this study tries to examine (1) the effects of PsyCap on burnout and engagement; (2) the influence of PsyCap on WFC and FWC; and (3) the moderating role of WFC and FWC in the relationship between PsyCap and psychological well-being when having children in women leaders. It is very important to identify the psychological personal resources that women leaders develop and the work-family demands that mostly interfere on their well-being, so the results of this study would be significant and meaningful to company managers to retain talent and contribute to the sustainability of the organization.

Literature Review
Compared with the large literature on subordinate employees, only few studies have focused on leaders' health, and when they are, have mostly been gender blind. In this line, Knudsen, Ducharme, and Roman [23] adapted the Job Demands-Resources (JD-R) model to leaders, taking into account job demands (i.e., performance demands and centralization) and resources (i.e., innovation in decision making and long-range strategic planning) specific of this sample, analyzing their relationship to emotional exhaustion (burnout) and turnover intention. Unfortunately, the authors do not provide information about the number of women/men leaders in the sample.
Focusing on a sample of female leaders, more studies have focused on the consequences of the Job Demands-Resources model (developed below) on performance. In this line, Bakker and Xanthopoulou [24] found evidence for the mediating effects of work engagement together with personal resources to increase leaders' creativity. Ribeiro, Bosch, and Becker [25] found that job demands promoted turnover intentions, whereas job resources had a negative effect on them. Also, they found a moderating role of mostly job resources on WFC and turnover intentions. However, although these studies were carried out with women leaders, an explanation of the results considering a gender approach is missing.
In summary, the JD-R model seems a good theoretical framework to understand women leaders' well-being. In the next sections, we will develop and broaden it by including the gender perspective.

Job Characteristics and Well-Being
Traditionally, occupational health psychology has focused on which job characteristics might affect workers' well-being. As stated by the Job Demands-Resources (JD-R) theory [26] and its updates [27], all types of job characteristics can be classified in one of two categories: job resources and job demands. Job resources refer to those physical, psychological, social, or organizational aspects of the job that are functional in achieving work goals, reduce job demands and the associated physiological and psychological costs, or stimulate personal growth, learning, and development [28,29]. Job demands are defined as those physical, psychological, social, or organizational aspects of the job that require sustained physical and/or psychological effort and are therefore associated with certain physiological and/or psychological costs [26]. These job demands and resources instigate two very different processes, namely a health-impairment process (burnout) and a motivational process (engagement). Burnout (BO) is defined as a syndrome of chronic exhaustion, a cynical, negative attitude regarding work, and reduced professional efficacy that could occur in any job [30]. Work engagement (ENG) is the mental state where employees feel full of physical energy (vigor), are enthusiastic about the content of their work and the things they do (dedication), and are so immersed in their work activities that time seems to fly (absorption) [31,32]. Although, originally, job resources were related mainly to the motivational process and demands to the impairment one, empirical results reported significant statistical interactions, showing that job resources can buffer the impact of job demands on strain [33][34][35].
In this line, the JD-R model proposes that job resources particularly influence motivation when job demands are high, which is consistent with Hobfoll's [36] notion that all types of resources gain their motivating potential and become particularly useful when needed.
Hobfoll [37] defines resources as the means to obtain a valued end (e.g., social support, work promotion, money) or as a valued entity in their own right (e.g., well-being, positive self-identity, and close attachments). The Conservation of Resources Theory (COR) [37] posits that individuals seek to acquire, maintain, and protect resources in order to reduce stress. Therefore, individuals are highly motivated to restore their resources when confronted with resource loss. The ability to gain resources provides emotional rest and increases the ability to maintain goal pursuit. Since resources are not in isolation, individuals develop their resources across their life span. The developmental characteristic of resource creation produces resource caravans, that is, sets of aggregated resources, e.g., personal resources such as PsyCap. Resource caravans may produce positive results in individuals' well-being [37].

Personal Resources (PsyCap) and Well-Being
Work demands related to role performance can cause negative effects on individuals' well-being when personal resources are consumed, or when individuals are unsuccessful gaining resources after considerable resource investment. On the contrary, those individuals who have sufficient personal resources can face these work requirements with no consequences for their well-being [38]. Then, going beyond the job characteristics as a main source of BO and ENG, lately the JD-R model proposes that personal resources can play a similar role to that of job resources, i.e., personal resources are expected to buffer the undesirable impact of the job demands on strain, and boost the desirable impact of (challenge) job demands on motivation. Personal resources refer to the beliefs people hold regarding how much control they have over their environment [27]. This proposition had limited support [39] when tested with optimism and self-efficacy, which stresses the need for more research to test the Job Demands versus Personal Resources interaction [27]. In this study, we go a step forward including PsyCap as a whole (and not only two of their components, i.e., self-efficacy and optimism) as a personal resource.
PsyCap is positioned as a mid-range "state-like" personal resource because the four constructs that constitute it have been conceptualized as both state-like and trait-like [40], making them relatively stable over time and susceptible of being developed [21]. PsyCap provides individuals with the motivational energy to keep striving for their goals addressing and surmounting the obstacles in their path to succeed [41]. The four components of PsyCap, namely hope, self-efficacy, resilience, and optimism, act synergistically as a result of their shared common variance [42]. PsyCap, as a set of personal resources, is consistent with the resource caravans proposed by the COR theory [37].
Hope is defined as a goal-oriented character strength [43], assumed to help individuals in adjusting to adversity [44]. The expectation of positive results produced by hope impulses individuals to persevere toward goals, redirecting their efforts if necessary, in order to obtain these goals [21]. Self-efficacy gives individuals confidence that they can succeed at challenging tasks [21], based on an actual belief or expectation that they can achieve a particular performance in a specific situation [45]. For Luthans et al. [21], being resilient is a resulting personal growth and development of facing challenging events. Resilience is a capacity that enables individuals to bounce back from adversity and adapt flexibly to changing demands. Being optimistic reflects one's global positive expectation [21] based on the positive attributions and expectations about the occurrence of specific events in a present, past, or future time [46,47]. Optimism refers to one's positive attribution about succeeding in the present and the future [18].
PsyCap has been positively related to job-performance and job well-being and life satisfaction [18,24,40,47] and negatively with work-burnout [6,38,48] and WFC-FWC [38,49,50]. Bakker and Xanthopoulou [24] suggest that personal resources such as PsyCap can be predictors of work-engagement because this personal resource gives employees an internal drive that allows them to transform into action (e.g., work-engagement) the opportunities provided by their job resources. As a result of its motivational nature, previous research [6,38,[51][52][53] has corroborated that PsyCap acts as a protective resource that prevents employees from feeling BO. Additionally, PsyCap allows employees to handle the conflicts when both family and work domains are interfering with one another [49] and avoid negative consequences on their job well-being [40].
PsyCap fosters individuals' cognitive appraisal of the demand of coordinating work and family responsibilities as a challenge, positively reframing it. Thus, individuals will rely on their personal resources and feel capable of managing work and family demands, perceiving more work-life balance [40]. It is plausible to suggest that navigating the labyrinth to the top has enabled women in leadership roles to develop a resource caravan [37]. In this line, Cheung and Halpern [19] propose that women leaders that had a high educational level also developed self-efficacy, and this provided them with upward mobility. Getting to the top could create a positive resource spillover for women leaders, helping them to manage the demands of their work and their family. Based on previous empirical research that suggests that PsyCap is a personal resource that enhances individuals well-being and enables them to affront inter-role conflicts, we expect that:

Work-Family Interference and Well-Being
Next to personal resources, the JD-R model can be expanded to include personal demands. Personal demands have been defined as "the requirements that individuals set for their own performance and behavior that force them to invest effort in their work, and are therefore associated with physical and psychological costs" [54] (p. 751). Studies in this line have included personal demands such as those regarding personality traits (such as performance expectations or workaholism; i.e., [54,55]). However, those studies have not taken into account other personal demands related to gender roles that might be affecting those relationships, mainly on women.
From a gender perspective, we consider that one personal demand that might be affecting those relationships with job BO/ENG is WFC and FWC, mainly on women. WFC and FWC are two directional dimensions of an inter-role conflict where work and family domains are mutually incompatible [56]. WFC is the conflict between work and family caused by work demands and FWC is the conflict between work and family caused by family demands [56,57]. WFC-FWC are a within-person across-domains transmission of demands and consequent strain from one area of life to another [58][59][60]. WFC-FWC occur when the resources associated with one role are insufficient to meet the demands of another role [61], defining this conflict as bidirectional phenomena by nature. As stressors, WFC-FWC erode mental health [60,62,63] while poor mental health undermines individuals' capacity to balance competing work and family demands [64][65][66].
Work-home interference has been studied in the context of JD-R model as a consequence (i.e., [67,68]) or as a mediating variable between job characteristics and related to BO and ENG (i.e., work pressure) [69]. However, as far as we know, only few studies have analyzed the role of personal resources such as PsyCap in leaders' work well-being [53] and less in women leaders [18,19].
Moreover, the career stage seems important when linking role demands and resources to work-family interface and its consequences on well-being. In this line, individuals in middle adulthood experience high WFC, but also high family-work facilitation due to the presence of high job demands and resources in both life domains [70]. It seems particularly important to check those results when considering women leaders in a top career position.
PsyCap can be argued to be part of personal resource caravans that enables individuals to cope with personal demands, affecting positively individuals' work well-being, and that WFC and FWC are inter-role demands that affect negatively work well-being. Therefore, we expect that: Hypothesis 4 (H4). WFC (Hypothesis 4a) and FWC (Hypothesis 4b) will mediate the relationship between PsyCap and ENG.

Having Children and Well-Being
Several studies point out how having children is a source of WFC and FWC. Parents with younger children at home report more conflict between work and family [71] and have fewer time and energy resources [63]. One setback for parents' ability to accommodate family responsibilities with work demands is the number of children they have [72][73][74]. Parents with younger children at home report more conflict between work and family [71] and have fewer time and energy resources [63]. Recent research has found that, when having children, WFC and FWC are negatively related to well-being [75] and mental health indicators [76].
It seems that WFC-FWC produce strains in family life, interfering with the time that parents and children can spend together and also influencing the emotional tone of family interactions [62,76,77]. Childbearing has been studied as one important factor of the family domain that negatively affects parents' WRC-FWC coping abilities [72][73][74] and mental health [76] when these parent reported WFC-FWC. Matysiak et al. [75] found that those individuals who received more resources for combining paid work with family life (e.g., from the state, partners, relatives, or employers) experienced fewer difficulties combining work-family domains. There is sufficient evidence to suggest that having children when experiencing WFC-FWC negatively affects work well-being, although these studies seldom include leaders nor particularly women leaders [19]. Hence, we put forward the following hypothesis: Hypothesis 6a (H6a). Number of Children (NCh) moderates the relationships between WFC and ENG such that the negative WFC-ENG relationship is strong when NCh is high and weak when NCh is low.
Hypothesis 6b (H6b). NCh moderates the relationships between WFC and BO such that the positive WFC-BO relationship is strong when NCh is high and weak when NCh is low.
Hypothesis 7a (H7a). NCh moderates the relationships between FWC and ENG such that the negative FWC-ENG relationship is strong when NCh is high and weak when NCh is low.

Hypothesis 7b (H7b). NCh moderates the relationships between FWC and BO such that the positive FWC-BO relationship is strong when NCh is high and weak when NCh is low.
In summary, working women face the challenges of the gendered expectations of commitment to work and commitment to family. These expectations may discourage women from career advancement and leadership positions [78]. Nevertheless, women leaders have managed to sort out the difficulties produced by these gendered expectations, counting mainly on their personal resources. Cheung and Halpern [19] found that women leaders, by integrating both roles, were able to successfully manage their work and family responsibilities. This role integration resulted from the use of strategies and personal abilities developed by women leaders throughout their life span. However, it has been broadly reported that WFC-FWC is an important source of strain for professional women causing differential effects on their work well-being in comparison with their male counterparts [52]. The number of children and their ages are all variables that have been associated with the conflict between work and family domains [71], but regardless of childbearing, personal resources reduce the impact of WFC-FWC on well-being [79]. Therefore, our final hypothesis are: Hypothesis 8a (H8a). PsyCap positively relates to ENG through WFC when NCh moderates the relationships between WFC and ENG.
Hypothesis 8b (H8b). PsyCap negatively relates to BO through WFC when NCh moderates the relationships between WFC and BO.
Hypothesis 9a (H9a). PsyCap positively relates to ENG through FWC when NCh moderates the relationships between FWC and ENG.
Hypothesis 9b (H9b). PsyCap negatively relates to BO through FWC when NCh moderates the relationships between FWC and BO.

Proposed Model
This study proposes nine theoretical hypotheses based on the aforementioned theoretical background and integrates them into a conceptual model (see Figure 1).

Proposed Model
This study proposes nine theoretical hypotheses based on the aforementioned theoretical background and integrates them into a conceptual model (see Figure 1). These hypotheses aim to analyze the mediation role that WFC and FWC plays between PsyCap and work well-being (work engagement and work burnout) when moderated by the number of children. It is expected that PsyCap has a direct positive relation with ENG (H1) and a direct negative relation with BO (H2). Because PsyCap enables individuals to affront their inter-role conflicts we expected a negative relation between WFC (H3a) and FWC (H3b) and PsyCap. Inter-role demands negatively affect work well-being, therefore we expected that WFC (H4a) and FWC (H4b) will mediate the relationship between PsyCap and ENG. Likewise, WFC (H5a) and FWC (H5b) will mediate the relationship between PsyCap and BO. Work well-being (ENG and BO) is affected negatively when having children and experiencing WFC and/or FWC. Therefore, we expected that on one hand, NCh moderated the relationship between WFC-ENG and WFC-BO such that the negative relationship between WFC and ENG (H6a) and BO (H6b) was strong when NCh was high and weak when NCh was low. On the other hand, we expected that NCh moderated the relationship between FWC-ENG and FWC-BO such that the negative relationship between FWC and ENG (H7a) and BO (H7b) was strong when NCh was high and weak when NCh was low. Due to the positive role of personal resources on reducing the effects of WFC-FWC on well-being we put out that PsyCap positively relates to ENG (H8a) and negatively relates to BO (H8b) through WFC when NCh moderates the relationships between WFC and ENG/BO. Similarly, PsyCap positively relates to ENG (H9a) and negatively relates to BO (H9b) through FWC when NCh moderates the relationships between FWC and ENG/BO. These hypotheses aim to analyze the mediation role that WFC and FWC plays between PsyCap and work well-being (work engagement and work burnout) when moderated by the number of children. It is expected that PsyCap has a direct positive relation with ENG (H1) and a direct negative relation with BO (H2). Because PsyCap enables individuals to affront their inter-role conflicts we expected a negative relation between WFC (H3a) and FWC (H3b) and PsyCap. Inter-role demands negatively affect work well-being, therefore we expected that WFC (H4a) and FWC (H4b) will mediate the relationship between PsyCap and ENG. Likewise, WFC (H5a) and FWC (H5b) will mediate the relationship between PsyCap and BO. Work well-being (ENG and BO) is affected negatively when having children and experiencing WFC and/or FWC. Therefore, we expected that on one hand, NCh moderated the relationship between WFC-ENG and WFC-BO such that the negative relationship between WFC and ENG (H6a) and BO (H6b) was strong when NCh was high and weak when NCh was low. On the other hand, we expected that NCh moderated the relationship between FWC-ENG and FWC-BO such that the negative relationship between FWC and ENG (H7a) and BO (H7b) was strong when NCh was high and weak when NCh was low. Due to the positive role of personal resources on reducing the effects of WFC-FWC on well-being we put out that PsyCap positively relates to ENG (H8a) and negatively relates to BO (H8b) through WFC when NCh moderates the relationships between WFC and ENG/BO. Similarly, PsyCap positively relates to ENG (H9a) and negatively relates to BO (H9b) through FWC when NCh moderates the relationships between FWC and ENG/BO.

Participants
The sample for the present study was recruited by contacting 46 professional and occupational women associations by email, asking them to spread the information about the research among their members. Depending on the requirements of the associations, two different versions of emails were sent. The first version of the email contained general information concerning the research team and an invitation to participate in the study via a link to the website of the research team, which gave access to the online survey via another link. In the second version, the email featured a brief summary about the research, and required the reader to participate by clicking on the given link to the on-line survey. Another recruiting strategy was through the research team LinkedIn profile, where information about the study was constantly posted, thus motivating women leaders to participate.
The total answers were 568. A total of 152 answers gave no gender information, 69 identified themselves as men, 346 as women and 1 as other: a person. From the sample of women leaders, only 202 (M age = 46.03, SD = 8.73) answers were complete (response rate = 58%); 90% of the final sample have university studies; and 74% have a partner and share the same household. The mean tenure in the job position was 8.98 years (SD = 8.07); 39% were senior managers, 32% middle managers, and 29% junior managers.
The study was approved by the University's ontological commission.

Procedure
Data collection was carried out in accordance with the ethical standards of the Ethics Committee of the University's ontological commission with written, informed consent from the participants as warranted by the Helsinki Declaration. We used several ways of contacting women leaders, mainly through professional online networks (i.e., LinkedIn), and through the contact with local and national professional and women leaders' associations. We asked these associations to distribute an email to their associates where the purpose of the whole project from which this study takes part was explained. The email included a link to a web platform containing the questionnaire items, along with instructions for completing them and the consent form. Participation was voluntary, anonymous, and confidential. The women leaders who agreed to be part of the study completed the questionnaire via the web platform, without any time limits. The online survey took an average of 20 min to complete. The data was collected during September 2018 and June 2019. The participants received no financial compensation for taking part in the study, but some results of the global study were fed back online.

Psychological Capital
Self-efficacy was assessed by a scale developed in this study based on Yukl's [80] taxonomy of leadership behaviors and Bandura's [81] suggestions for constructing self-efficacy scales. To develop the scale, we conducted a focus group with nine women leaders in order to explore their perception of which leadership behaviors are difficult to perform in their leadership roles. The most difficult behaviors to perform were: (a) clarifying, (b) monitoring operations, (c) supporting, (d) empowering, (e) envisioning change, and (f) encouraging innovation; corresponding to the following behavior meta categories: task-oriented, relation-oriented, change-oriented, and external, respectively. The average difficulty level was 7.58. A differential element emerged: the balance between family and work responsibilities, as an element that hinders the performance of leadership. The items were constructed based on these difficulties. The scale was reviewed by psychologists with expertise in leadership and by women in leadership positions, who signaled out the items which were difficult to understand. The items were rewritten and reviewed. The final version of the scale has 12 items (α = 0.82): three items correspond to the "clarifying" behavior category (e.g., "I can explain the tasks to the people under my supervision even when the interaction time is limited"); two of them correspond to the "monitoring operations" category (e.g., "I can help the people under my supervision when they are having a problem to maintain the focus on the solution and not on the problem"); one of them corresponds to the "supporting" category (e.g., "I can give support to the people under my supervision even when I have many tasks pending"); one of them corresponds to the "empowering" category (e.g., "I know who I can give a new task to among the members of my team, even when they have not done it before"); one corresponds to the "envisioning change" (e.g., "I can communicate the vision of the organization in a clear manner"); two of them correspond to the "encouraging innovation" category (e.g., "I can encourage the people under my supervision to initiate innovative actions even when they are not convinced of the change"); and one of them corresponds to the "networking" category (e.g., "I can have meetings and make contacts with other people and/or companies to promote the businesses of my organization even though most of the people with whom I interact are of the opposite sex"; one item asked about the difficulties to balance work and family responsibilities (e.g., "I can reconcile my work activities with personal and/or family ones even though I have many demands at work"). Participants rated all the items on a seven-point scale from 1 (totally in disagreement) to 7 (totally in agreement).
Hope was assessed by four items (α = 0.76) (e.g., "Currently I think I am having some success in my job") and optimism by two items (α = 0.67) (e.g., "Considering my job, I always see the bottle half full") from the Psychological Capital Questionnaire 12 [84]. The scale was sent to the authors after contacting and requesting authorization through their webpage (www.mindgarden.com) to use its Spanish version. The scale was validated to the Spanish sample by López-Núñez, de Jesús, Viseu, and Santana-Cárdenas [85] in 2017.
In the present study, the PsyCap measure demonstrated an acceptable internal consistency reliability (α = 0.88).

Engagement
This variable was measured by the Spanish version of the UWES (Utrecht Work Engagement Scale) by Schaufeli, Salanova, González-Romá, and Bakker [86]. This scale has three subscales consisting of three items each: vigor, dedication, and absorption. Altogether, the engagement scale demonstrated an acceptable internal consistency reliability (α = 0.88). Participants rated all the items on a seven-point scale from 1 (never) to 7 (always). An example of an item of vigor is "At work, I feel full of energy." An example of a dedication item is "My work inspires me." An example of an absorption item is "I am immersed in work".

Burnout
The Spanish version of the MBI-GS (Maslach Burnout Inventory-General Survey) questionnaire [87] was used to measure burnout (α = 0.82). Specifically, the cynicism and emotional exhaustion scales of 4 items each were used. An example of a cynicism item is "I have lost interest and enthusiasm in this work." An example of an item of emotional exhaustion is "It is getting harder for me to get up to go to work". Participants rated all the items on a seven-point scale from 1 (never) to 7 (always).

Family-Work Conflict
This variable was measured by 6 items (α = 0.86) from the 2017 Spanish survey of "Use of time" (www.cis.es) conducted by the Centre of Sociological Research-CIS (its acronym in Spanish). The heading of the questions was "How often throughout your working life would you say that any of the following situations have happened to you because of caring for your children or dependents?" and the items were the following: (a) Miss a training opportunity; (b) Miss a promotion or a promotion opportunity; (c) Have limitations on salary/less income; (d) Absences at work (having to go to the doctor with a child, etc.); (e) Have worse schedules or work shifts; (f) Less access to positions of responsibility. Participants rated all the items on a seven-point scale from 1 (never) to 7 (always).

Work-Family Conflict
This variable was measured by 3 items (α = 0.71) from Martins, Eddleston, and Veiga [88]. The items were the following: (a) I suffer stress or problems that frequently affect my family or private life; (b) I can't spend the time I would like with my family or friends; (c) I have to stop doing important things about my household or related to my family to get in touch with work. Participants rated all the items on a seven-point scale from 1 (totally disagree) to 7 (totally disagree).

Data Analyses
To examine whether WFC and FWC mediate the relationship between PsyCap and ENG and BO when moderated by NCh, we performed moderated mediation analysis using Model 14 four times in the PROCESS tool version 3.3 [89] for SPSS (version 25). According to Hayes [90] the moderated mediation model proposed is a second stage moderation model, having one moderator. Specifically, this model allows the effect of the mediator (WFC/FWC) on the dependent variable (ENG/BO) in a mediation model to be moderated by NCh while fixing the effect of PsyCap on the mediator (WFC/FWC) to be unmoderated. The centering and interaction terms and the point estimate and firstand second-order variance estimates of the conditional indirect effect for a given set of moderator values, are automatically determined and provided by the PROCESS macro. Table 1 shows the descriptive statistics, correlation analysis, and reliability analysis for the variables. As shown in Table 1, PsyCap was negatively related with FWC (r = −0.17, p < 0.05) and with BO (r = −0.39, p < 0.01), also PsyCap was positively related with ENG (r = 0.40, p < 0.01). FWC was positively related with WFC (r = 0.04, p < 0.01) and with BO (r = 0.40, p < 0.01). ENG was negatively related with BO (r = −0.44, p < 0.01).

Hypothesis Testing
The results of testing the indirect effect of the moderated mediation model (PROCESS, Model 14) are presented in three steps. The first step reports the interaction of PsyCap on the mediators (i.e., WFC and FWC). The second step reports the effects of PsyCap, WFC/FWC, and their interaction terms with NCh, and the effects of NCh on the dependent variables (i.e., ENG and BO). The results of the first and second steps are presented in Table 2 for Work-Family Conflict and Table 3 for Family-Work Conflict. The third step results concern estimates of the conditional indirect effect, and the corresponding 95% bootstrapped confidence intervals, which are shown in Table 4 for Work-Family Conflict and Table 5 for Family-Work Conflict.    As shown in the mediating models of Table 2 when not in presence of WFC, the direct effect of PsyCap on ENG is positive and significant, whereas it is negative and significant on BO (ENG: Coefficient = 0.62, SE = 0.09, p < 0.001, R 2 = 0.21; BO: Coefficient = −0.61, SE = 0.12, p < 0.001, R 2 = 0.28). Table 3 shows that the direct effect of PsyCap on ENG is positive and significant (coefficient= 0.59, SE = 0.10, p < 0.001, R 2 = 0.00), whereas it is negative and significant on BO (coefficient = −0.76, SE = 0.76, p < 0.001, R 2 = 0.18) when not in presence of FWC. H1 and H2 were supported.
As Table 2 shows, when predicting the effects of WFC, the coefficients of the independent variable PsyCap (Coefficient = −0.43, SE = 0.17, p < 0.05, R 2 = 0.03) were negative and significant, meaning that when PsyCap is high, WFC is low. H3a was supported. As shown in the mediating models of Table 3, PsyCap does not directly affect FWC, the coefficients of the independent variable PsyCap (coefficient = −0.22, SE = 0.19, ns, R 2 = 0.01) were negative and non-significant. H3b was not supported.
The index of moderated mediation is estimated using the data available and is subject to sampling variability. Hayes [90] recommends a bootstrap confidence interval to test the null hypothesis. Thus, the indirect effects of the moderated mediation were tested using the bootstrapping procedure (based on 5000 resamples). Observing Table 4, we can point out that the estimates of the bootstrapped indirect effects of PsyCap on ENG and BO through WFC when moderated by NCh indicated that when NCh was low, PsyCap did not have a significant effect on ENG (Effect  (H8a). Nevertheless, there is a partial support for H8b, since PsyCap has a negative effect on BO through WFC when NCh has the value of the mean or is high. Table 5 shows the estimates of the bootstrapped indirect effects of PsyCap on ENG and BO through FWC when moderated by NCh. These estimates indicate that when NCh was low, on the mean value or high, PsyCap did not have significant effects on ENG nor BO. These results did not support H9a and H9b.

Discussions
This research contributes to the psychology of sustainability approach understanding women leaders' well-being. The study among women leaders aimed to analyze the mediation role that WFC and FWC plays between PsyCap and work well-being (work engagement and work burnout) when moderated by the number of children, providing evidence for the relevance of the psychology of sustainability research, encouraging sustainable and healthy working conditions in organizations based on gender equality. The main contribution of the study was the inclusion of PsyCap as a whole, as a personal resource and as an antecedent of work well-being. In addition, we focused on a sample of women leaders considering a gender perspective. As far as we know, only few studies have analyzed the role of personal resources such as PsyCap in leaders' work well-being [53], particularly in the case of women leaders [18,19], and even in these, the gender perspective was missing. Then, we analyzed the role played by WFC, FWC, and the number of children in the relationship between PsyCap and the work well-being (ENG and BO) of these women working in top positions. Integrating the proposed theoretical relationships, a conceptual model was developed and tested using empirical data collected from 202 women leaders. The hypotheses testing results have the following key theoretical implications, limitations, and practical implications.

Theoretical Implications
Our results show that WFC mediates the relation between PsyCap and BO, but not with ENG when women leaders have children. We also found that FWC does not mediate the relation between PsyCap and ENG nor BO. In addition, the results clearly show that PsyCap acts as a protective resource of women leaders' work well-being.
These results expand on the previous research [24] where PsyCap played a positive role enhancing women leaders' work-engagement (H1) and employees in general [22,47]; and a negative role with work-burnout (H2) in leaders [53], in female doctors [52] and in teachers [6,38].
As a personal resource, PsyCap gives women leaders the motivational energy to pursue their goals and persist in their accomplishments even when difficulties arise. In each of the four dimensions, PsyCap provides women leaders with the personal resources in order to overcome the complex, pressure-packed work-demands and the resulting stress that it could involve [18,53]. Hope provides women leaders with the positive expectation to succeed in finding alternative pathways to achieve their goals [21]. Self-efficacy gives women leaders the confidence about their abilities to overcome the challenging demands of a skeptical society and workplace about their leadership skills and competence [14,16]. Women leaders continuously face the setbacks produced by the gender bias and gender discrimination, outgrowing them. Their resilience builds up from this adversity, and gives women leaders the capacity to adapt to the changing demands they confront [21]. The labyrinth to the top of organizations [16] suggests that it is difficult to navigate, but not impossible. In this regard, optimism allows women leaders to positively reframe the setbacks experienced, enabling them to keep positive expectations about their achievements in the future [21].
As it has been reported, leaders have personal resources [18,53] to face their work demands enhancing their well-being. According to Bakker and Xanthopoulou [24], resourceful individuals may actively create engagement experiences by rearranging their tasks, job content, or assigning meaning to their jobs or tasks; practices which are at hand for women leaders. Roche, Haar, and Luthans [53] found that senior managers had higher levels of PsyCap in comparison with those managers of lower leadership levels. In our study, the PsyCap mean was very high (5.86), suggesting that women leaders may develop personal resources as a consequence of navigating the labyrinth to the top. This development of resources supports the idea of the caravan of resources stated by the COR theory, where sets of resources act together to reduce the demands that individuals face.
We expected PsyCap as a personal resource to reduce the perception of having a WFC (H3a) and a FWC (H3b), as both are an inter-role conflict that could be faced by the energy and perseverance provided by PsyCap. Our results were not consistent with existing research, where FWC was reduced by PsyCap in women [48,52,79] suggesting that women leaders' family care-taking demands do not interfere with their career development, not being in need of using their PsyCap in order to reduce these demands. Thus, women leaders are able to manage the demands emerging from their family life, making it more permeable to their work than vice-versa [38]. Conversely, the negative relationship found between PsyCap and WFC is consistent with existing research [48,79,91]. It is likely that women leaders perceive that their work-role and work-demands require-whether implicitly or explicitly-to put them first having a WFC, facing this conflict resorting to their PsyCap.
Contrary to what is hypothesized in this study, WFC does not significantly act as mediator of the effect of PsyCap on ENG (H4a); nor FWC significantly acts as mediator of the effect of PsyCap on ENG (H4b) nor on BO (H5b). As suggested by Demerouti, Peeters and van der Heijden [92], women leaders could be under high job demands when exerting their work-roles but also rely on their personal and job-resources to reduce the conflicts of both family and work domains. Consistent with the precepts of COR theory [37], women leaders' job-role generates enough resources to make them vigorous, dedicated, and absorbed because of their work. The engagement that women leaders' experience could be a result of their continuous efforts to obtain and maintain the resources which help them overcome the possible conflicts between their work and family domains.
More importantly, the results suggest that WFC acts as mediator of the effect of PsyCap on burnout (H5a). Women leaders with high PsyCap levels are capable of minimizing the stress suffered as a consequence of work-demands affecting family-life that will not lead to elevated burnout. In this regard, COR theory [37] suggests that PsyCap mitigates women leaders' conflicts in the work-family interface by supplementing the energy consumed by WFC. Due to the gendered expectations about women's roles, balancing family responsibilities with working responsibilities is a challenge for women with paid-work. The root of this conflict is the gendered nature of organizations structured according to male values and norms and the presupposition of someone (usually women) taking responsibilities of domestic and family tasks [93]. It is clear that personal resources are key for women leaders to overcome WFC, preventing them from feeling a chronic exhaustion, having a negative and cynical attitude regarding work, and reducing their professional efficacy [38,48,91].
Regarding childbearing, the literature reports that-as a source of WFC and FWC-it negatively affects well-being [75] and mental health [76] of parents at home. For instance, it has been found that the number of children [72][73][74] undermines parents' ability to adjust family responsibilities with work demands. Similarly, the current study found that the number of children had lowers levels of engagement (H6a) when experiencing WFC, along with higher levels of burnout (H6b). However, our findings also indicated that when experiencing WFC, the number of children has no impact on engagement (H7a) or burnout (H7b) of these women leaders.
Finally, the current study has explored the mediation effect of WFC/FWC on the linkage between women leaders' PsyCap and work well-being, and whether this mediated relation was moderated by the number of children these leaders have. When experiencing WFC, NCh moderates positively but non-significantly the relation of PsyCap with ENG when NCh was at 1 SD (H8a) (see Table 4, engagement). However, NCh moderates negatively and significantly the relation of PsyCap with BO. The moderated effect of NCh on the linkage of PsyCap and work burnout through WFC is consistent with research findings seeking to explain the effects of WFC and childbearing on parents' well-being [63,[71][72][73][74][75][76]. However, when women leaders experience FWC, our study revealed that NCh moderates negatively, but non-significantly, the relation of PsyCap with ENG (H9a) or BO (H9b). Thus, the main and significant role played by PsyCap is lessening the experienced negative and cynical attitude regarding work, and the perception of a reduced professional efficacy of women leaders' with WFC when having more than one child (H8b) (see Table 4, burnout).
Women leaders have overcome the difficulties of the indirect paths that took them to the top of the organization, being continuously scrutinized because of the incongruity between their gender and their role as leaders [14,16]. Additionally, despite the success in their professional career, women leaders are not granted to be exempt of the gender expectations about their gender role in the family domain. Gender biases and standards [93] affect women and men's professional careers differently [78]. Working mothers are first considered mothers, then professionals, having to constantly prove that they are committed to work in order to advance their careers [78]. Working women with children suffer penalties that fathers do not. For working women, having children affects their salaries negatively [19], their career development opportunities, and their opportunities to become leaders [78]. Nearly half of top executive women have no children [19]; this is because gender assumptions place women in a position where they have to choose to be "good" mothers or ideal workers. Hence, women who have leadership aspirations are hinted by organizational clues, that in order to make it to the top, the requirement for them is not to have children. Gendered expectations place women leaders who have decided to be mothers in a position where they experience a variety of stress and strain as they navigate the labyrinth to the top [16,78]. Being leaders and mothers diminish women leaders' work well-being because they find themselves caught between their family roles and their work roles.
Our study makes a key contribution to the existing knowledge concerning the challenges that women leaders face when balancing their work and family responsibilities, i.e., their double burden. The double burden or second shift has shown to be related to female work absenteeism [94]. In particular, some studies show that the higher number of children, the lower the sickness absence [95]. In this line, our findings suggest that women leaders who have children do not perceive a FWC because they count on their personal resources to successfully manage the family demands that affect their work, so the effect on well-being (burnout and engagement) is low. Women leaders with children who were able to manage their FWC demands depend mostly on their personal resources to implement different strategies, allowing them to integrate their work and family responsibilities [19]. One of those strategies seems to be taking care of the FWC demands by externalizing them-keeping the mental load or their management-usually leaning on other women [96]. The integrator type for work-life management consists of combining family and work roles during the working day [78]. Furthermore, women leaders with children extend their reliance on their personal resources to attenuate the negative effect of WFC on their work well-being. The conflict between work-domain and family-domain demands is a consequence of inadequate organizational cultures and policies concerning work-life balance and diversity management. Thus, women leaders are forced to rely on their personal resources to cope with this conflict when it should be addressed by the organizations. In summary, women leaders' personal resources are key factors for managing appropriately their double burden. Nevertheless, there are different mechanisms: personal resources boost their abilities to manage FWC, whereas their effects on WFC seems not to be so effective, as they continue affecting their well-being. Therefore, "well-publicized organizational policies and practices that normalize more flexible work schedules and prioritize quality of work over 'time served' would be a tremendous help in overcoming work-life obstructions to increased involvement by women in leadership roles" [97] (p. 316).
According to the UN SDGs shared goals, our research shows that much work needs to be done to achieve gender equality, healthy companies, and to enhance women's wellbeing. Regarding gender biases and masculinized organizational cultures, organizations must change their narratives and cultures to gain sustainable development. Women leaders' well-being has to be one of the backbones for organizations and societies to become healthier. Hence, organizations should end the gender biases that impede women leaders balancing their work and family responsibilities, thus allowing their professional careers to develop as their male counterparts careers do. Only by creating conditions that enhance employees' health within a healthy work environment, makes ending the WFC, FWC, and BO possible, and thus achieving SDGs. Personal and organizational narratives must be integrated as a driver for successful sustainable organizations. Nevertheless, much research is needed to expand the knowledge of the psychology of sustainability approach to understand women leaders' well-being and SDG's gender equality.

Practical Implications
According to the psychology of sustainability and sustainable development, healthy organizations [2] should seek the balance between the individual's, group's, organization's, and society's needs and requirements. Multilevel intervention approaches in organizations should optimize well-being through practices, policies, and work environments framed in an organizational culture of diversity. Healthy and sustainable organizations need to nurture well-being by optimizing the use of personal resources as PsyCap, promoting the conservation of these resources by creating resourceful work-environments with job demands that do not have the capacity of draining completely the individuals' available resources.
Also, the results of our research emphasize one of the main ideas of the psychology of sustainability and sustainable development that is the consideration that organizations need to change the narrative perspective by fostering a diversity management framework [98] that accommodates different value, roles, and behaviors systems that promotes healthy business and employees.
To achieve gender diversity management to promote healthy employees and leaders, organizations should go beyond structural solutions to the roots of inequity [78,99]. Understanding the roots of gender inequity, leadership in organizations implies exploring issues such as the gendered expectations concerning work and family, the bias and stigmas associated with using time-flexibility policies, and the separation of employees' professional identity and parental identity.

Limitations and Further Research
The contributions of this study should be considered in light of its limitations. In the first place, the cross-sectional design of the study limits us from establishing the causality of the tested model. However, most of our findings were consistent with theoretical predictions and with empirical research, and our findings provide further confirmation of this. Nevertheless, our results did not report that FWC had a mediation role between PsyCap and work well-being, future research should address the disparity of our results with theoretical and empirical proposal of the observed phenomenon. Longitudinal studies may examine and broaden the relationships found in our study.
Secondly, we used self-report measures and single-source design for all of our variables, which could have produced common method bias variance. Data collection only by self-report scales could affect the veracity of the information obtained, notwithstanding the moderate correlations among the study variables should not raise concerns about a common-method bias in our study. Following the recommendations of Podsakoff, MacKenzie, Lee, and Podsakoff [100], we intended to minimize this potential limitation via the anonymity of the respondents' answers and by assuring respondents that there were no right or wrong answers and that they should be as honest as possible when answering the questions. Additionally, guaranteeing the veracity of the information obtained by including an anonymity clause limited the possibility of performing a longitudinal study. These limitations may be addressed by future studies using multi-source research designs.
Thirdly, the composition of the sample may limit the generalizability of the results. The current sample was homogeneous concerning gender, and varied in terms of years of experience, tenure, work-places, economic sector, and hierarchical levels. Research with a gender perspective [101][102][103] highlights the importance of intersectionality as a theoretical approach to understand the ways in which identity elements interact within a specific social identity, namely a woman leader. Further research with more balanced samples in terms of these variables would contribute to the generalizability of the findings among women leaders, and contribute to extending the generalizability of the current findings across gender, race, class, and nationality.
Another area for future research would involve analyzing the interaction of gender, family, and work to understand the complexity of women's leadership. Additionally, this research might explore the differences between women leaders' work well-being when working in organizations with a gender equality culture. For example, future research could check whether in organizations with more gender equality culture, women leaders have to rely on their PsyCap when managing inter-role conflicts between their work and family domains when having children. It would be interesting to compare female and male leaders in different organizational gender-cultures on the benefits of PsyCap as positive psychological resources and gender equality policies in work well-being.

Conclusions
One of the key conclusions of the current study is that PsyCap has the ability to reduce the strain that WFC puts on the work well-being of women leaders when having children. PsyCap is a mid-state-like personal resource amenable to being developed by targeted intervention [21]. In line with previous research [18], our findings support the idea of the positive impact of PsyCap and a gender-equitable workplace on the well-being of women leaders. These findings have potential implications for sustainable and healthy organizations, as one of the backbones of sustainability development is gender equality. Hence, organizations have the opportunity to develop women leaders' PsyCap by training interventions to ensure them a caravan of resources to ensure their well-being; and also, to promote gender equality through policies and practices involving the balance of work and family responsibilities.
Gender diversity is important throughout organizational levels and in leadership positions. Gendered assumptions about leaders' qualifications and skills and about work and family roles should be replaced by a culture of diversity in organizations. This cultural change towards diversity will help women to envision themselves as leaders and men to be prone to participate actively in their family responsibilities without being stigmatized for it [78].
Sustainable and healthy organizations should promote the use of work-life balance policies by both men and women who want to engage in caregiving responsibilities without experiencing conflict or strain. To foster a culture of diversity prevents the stigmatizations of women and men for using policies designed to balance work and family domains. Those changes performed by organizations to assure gender equality should promote an organizational culture of work-life balance that normalizes in organizational practices, the use of policies designed to balance family and work domains.
In this regard, new awareness about the psychology of sustainability and sustainable development needs prevention plans to foster healthy work environments that might be created through the concept of health-promoting leadership [104] as a leadership style for creating conditions enhancing the multidimensional relationships between work environments, personal life, and individuals' well-being.
Future psychology of sustainability and sustainable organizations requires "liquid" [2], healthy organizational processes which manage to interlope fluidly the multifaceted environments where women and men work and live.