Anthropologist Symons (Univ. of Cal., Santa Barbara) presents a sophisticated and scholarly analysis of human sexuality biased by the tenets of sociobiology. These are the assumptions that basic human behavior is guided by a bio-logic (his usage) demonstrated as reproductive fitness. In the case of sexuality, this assures essential differences in males and females. Males seek variety, are more easily aroused, gain by having multiple partners, are attracted by youth and beauty. In contrast, females stand to lose if they seek variety, look for prowess and power as much as physique, are less easily aroused, and behave as though sex were a service performed for other gains. The much-labored early parts of the book make the plea for parsimony in social science, argue testily against using monogamous gibbons as pre-hominid exemplars, and attack the notion of the pair-bond promoted by Morris et al. as irrelevant to the institution of marriage. Female orgasm and menopause are dismissed as artifacts rather than adaptations. Symons okays the use of chimpanzees as examples, however, and the recent evidence that male chimps in the wild collaborate in warfare and murder, or individually practice rape, becomes so much grist for the sociobio mill. Still, one must admire Symons' skills at presenting his case. As he moves into the ethnographic evidence and contemporary biography, fiction, and statistics (e.g., Kinsey, Hite) he may be guilty of selectivity, but on the whole one can agree that, yes, sex is different and means different things to men and women. His argument that homosexual behavior bears this out--with male homosexuals acting individually like males, and lesbian pairs like heterosexual couples--also seems cogent. The real issue lies in the assumption that bio ""logic"" is both necessary and sufficient to account for much of human behavior, and that only characters which confer positive biological advantages ultimately can survive. Equally problematical is the possibility of separating sexual behavior and emotions from other complex human motivations and emotions, and, in turn, determining the extent to which learning, lore, and language can influence natural selection.