This chapter provides an overview of the neuroendocrinological mechanisms underlying mammalian reproduction. It focuses on discoveries made in the past two decades, integrating both male and female reproductive behavior. The mechanisms that underlie sexual behavior range from the social composition of the group to coactivators that bind with steroid receptors to stimulate transcription and translation of new proteins in the brain. “Sexual behavior” refers to behaviors associated with courtship, mating, and copulation and not those associated with maternal behavior, territoriality, lactation, etc. It integrates male and female sexual behavior (MSB/FSB) in mammals and compares the mechanisms that underlie each. Males have been examined from two perspectives: one that deals with the mechanics of copulation and another that investigates the motivational aspects of copulation and, more recently, how this is associated with reward. Female sexual behavior traditionally has been used as a bioassay to map steroid-dependent spinal cord to brain circuits. The most stereotyped aspect of the behavior, lordosis, is the rigid posture that female rodents assume in response to stimulation of the hindquarters.
