On Human Nature

A necessary element of analyzing the human species through a sexual lens is recognizing that sexual activity is more expansive than a dichotomy of reproduction and pleasure. If either of these two goals, or their conjunction, were the sole goals, then nature would have found a more efficient way to do so: “sex is in every sense a gratuitously consuming and risky activity” (122). It takes time and resources, and has a generally low rate of success (reproductively speaking). The reason why sexual dimorphism and reproduction are present in mammals is simple: “sex creates diversity” (122). In asexual reproduction, offspring are exactly like their parent organism; in sexual reproduction, offspring combine genetic material from two parents, resulting in genetic diversity that is impossible to achieve otherwise.

Genetic diversity is the best adaptation against the possibility of a changing environment that would render a species’ current adaptation ineffective. One of the obstacles that sexual dimorphism creates, however, is male/female conflict and aggression: “conflict of interest between the sexes is a property of not only human beings but also the majority of animal species” (124). The males of most species are rewarded for aggression and assertiveness, while females are often rewarded for patience and high selectivity (of mates). This has led to a double standard in most cultures’ acceptance of sexual activity between the sexes: While “three-fourths of all human societies permit the taking of multiple wives [...] marriage to multiple husbands is sanctioned in less than one percent of societies” (125-26).

Outside of sexual activity and reproduction, sexual differences in male and female anatomy—determined by genetics—result in physical differences that shape the way societies function. The average man is, on average, significantly stronger, heavier, and quicker than the average woman: “The proportion of their limbs, their skeletal torsion, and the density of their muscles are particularly suited for running and throwing, the archaic specialties of the ancestral hunter-gatherer males” (127). Male physicality has resulted in various temperamental differences between the sexes due to the tasks expected of males in most societies, and this in turn has “been amplified by culture into universal male dominance” (128).

The evidence is clear that “modest genetic differences” (129) exist between male and female individuals of any given species; their behavioral genes interact with a given environment to create divergences in psychological behavior at a young age. These differences are later amplified “by cultural sanctions and training” (129); the average differences between mature men and women are due to a combination of inherited genetics and culturally conditioned ways of manifesting masculine and feminine traits. In other words, gender identity is a combination of nature and nurture.

While “the universal existence of sexual division of labor is not entirely an accident of cultural evolution” (132), variations are due to cultural evolution—and so modernity must decide which structural features to accept and which need to fade away. By making use of “the instruments of education and law” (147), every society gets to decide how to progress the fields of sexual behavior, sexual discrimination, and family structure.