The general principles of natural selection are not inherently sexist and simply stated propose that individuals vary; some variations are more favorable than others; some of this variation is heritable; differential reproductive success may occur; and differing gene frequencies may result. Sociobiology is the study of social behavior as determined by biology, and is essentially based on elements of evolutionary theory emphasizing natural selection as a mechanism by which evolution can occur (Dunbar, 1982; Simpson, 1972). However, sociobiology as applied to humans (Lumsden & Wilson, 1981; Wilson, 1975) is seriously flawed. The concepts of sexual
selection and parental investment which have grown out of theories of natural selection, now encompassed by the larger rubric of sociobiology, have been particularly subject to sexist constructions, and have been accorded a certain degree of legitimacy by virtue of frequent repetition, even prior to the advent of sociobiology.
Sexual selection refers to selective pressure on particular traits through conspecifics rather than other environmental factors. The cornerstone of sexual selection is competition (occurring most frequently among males) for access to mating partners (females). The mechanism of sexual selection is thought to account for spectacular physical ornamentation and exotic courtship behavior exhibited by males. Parental investment is a concept closely related to sexual selection regarding the “behavior of a parent toward its offspring that increases the chances of that offspring’s reproductive success at the cost of the parent’s investment in other offspring” (Barash, 1982, p. 393). Trivers’ paper outlining the parental investment concept (1972) has become an institution in itself, and still emanates through the natural and life sciences literature, being cited as often as 100 times per year. Trivers used Bateman’s (1948) work with Drosophila, conjoined with the theory of sexual selection, in his contention that males and females differ significantly in the likelihood of reaching their maximum breeding potential.
The gist of parental investment theory is that males and females incur different initial biological costs and opportunity costs in the conception and incubation of offspring. It is argued that males benefit by mating with as many females as possible, whereas females benefit most by taking special care in choosing a mate that can provide protection, if not direct support, for the rearing of offspring. Males have the potential for a high breeding rate by courting, mating, and then leaving one female for another, whereas (mammalian) females, once pregnant, have committed their biological resources and any other breeding opportunities. The bottom line, according to parental investment theory, is that optimal mating strategies are not equivalent for females and males. Naturally, if one sex (female) is seen as contributing more to reproduction, then that sex also can be seen as having more to lose. Presumably, this would foster cautious mating behavior on the part of females and impulsive sexual behavior on the part of males. In the following sections we address the misapplication of these ideas and their general flaws.