Casual sex differential
On average, men are more interested in casual sex than women. This differential has persisted through a variety of cultural contexts (a):
More than that, the difference persists even when society pushes against it. As Donald Symons points out, men’s stronger interest in casual sex and sexual novelty has survived society’s best efforts to eradicate it.
It has survived the efforts of parents, partners, and moralists to inculcate men with a healthy respect for monogamy.
It has survived Christian moral teachings and threats of eternal damnation.
It has survived cultural and legal institutions that endorse and incentivize lifelong monogamous marriage.
It has survived worries that one might lose one’s marriage, one’s children, or even one’s livelihood over an adulterous affair that won’t stay hidden.
And it has survived pop psychological attempts to stigmatize men’s desire for casual sex by blaming it on psychosocial immaturity, psychological maladjustment, repressed homosexuality, low self-esteem, fear of commitment, a Peter Pan syndrome, misogyny, male entitlement, toxic masculinity, and rape culture.
Meanwhile, women’s greater reticence about casual sex has survived the efforts of some feminists and other thought leaders to persuade women to cast off the shackles of patriarchy and match men in the casual sex arena.
This is all rather awkward for the Nurture Only theory. It suggests that, rather than being a product of culture, the sex difference in attitudes to casual sex often emerges in spite of culture.