HUMAN FEMALE sexuality is now acknowledged to be the end result of a complex interaction of biological, sociocultural, and psychological factors, with the latter two factors being seen as more important by many authors.1,2 The purpose of this communication is to review recent findings in animals and humans related to hormonal influences on female sexual behavior. It is recognized that genetic3,4 and experimental5-8 factors are also important in the final end product of adult sexual behavior, but these will not be considered at this time. The effects of hormone on animal behavior not instrumentally concerned with sex will also be neglected for the purpose of this presentation. Observations in Animals Many species of low mammals show sexual behavior only in response to periodic ovarian activity and secretion of estrogen. In some species, small amounts of progesterone are needed for maximal sexual