ABSTRACT
The major biological feature that differentiates the sexual cycle of primates from that of other mammals is its multicyclicity, a characteristic that presumably has particular survival value for the species. At the same time, if one considers vulnerability of the female sexual cycle to neurogenic stress, such cyclicity increases the likelihood of neurogenic sexual disturbances. Because the possibility of important phases of the sexual cycle coinciding with different stressful conflict situations acquires greater significance than in animals without cycles or with cycles of longer duration. The sexual activity of primates is regulated by neural and hormonal mechanisms that under healthy conditions produce a regular cyclicity. Normal sexual cycles in all mammals, including primates, are biphasic. The periodic swellings of the "sex skin" and menstruation serve as two outward manifestations of the sexual cycle in baboons. The swelling of the sex skin is a particularly distinct and useful index of the stage of the cycle in this species.
