The “gender revolution,” the monstrous sequel to the sexual revolution, may prove momentarily diverting, but we cannot get away from the birds and the bees. The origin of each human being is the fusion of sperm (from a male) with ovum (from a female). At the moment of fertilization, the combination of these male and female gametes creates an additional, distinct, and complete set of chromosomal DNA: a new person. Bringing sperm and ovum together is the easy part (indeed, it is so easy that it is often done accidentally), but to create a new person in such a way that his parents are both equipped and willing to raise him, we need some other incentive. While “love” sounds nice enough, historically, it has been marriage — understood as a lifelong union based on the complementarity of the sexes, primarily for the purpose of producing and rearing children — that fulfilled this social role. Though this connection between babies and marriage was once obvious, the wider availability of contraception at the turn of the 20th century began this great unraveling. By 2013, a Pew Research Center survey found that while 88 percent of people thought “love” was an important reason to get married, only 49 percent thought “having children” was important. Children became a marital afterthought. A symptom of this, though by no means a cause, is the growing acceptance of same-sex marriage. (Same-sex relationships are, by their nature, not geared towards reproduction. But today, this is generally considered to be insignificant.) The promise of the sexual revolution was that we’d have more choice and we’d all be happier for it. But this was predicated on the idea that people make choices with great conviction and independent of social expectation when they obviously don’t.