All this may sound horrible today, but some of it had a harsh underlying logic. For most of history, a man had no reliable way to tell whether he was the biological father of a child and, in a world where nearly everyone was poor, most were reluctant to risk wasting bread on another man’s offspring. Many therefore asserted oppressive control over female fertility, forbidding their wives and daughters to mingle with other men and—in the Athenian case—claiming the right to kill any child they did not wish to acknowledge.

In “Fatherhood: A History of Love and Power”, Augustine Sedgewick, an American scholar, describes how thinking about dads has changed over time. What is striking is the sheer variety of nonsense that people have believed.

• Aristotle? Hotter sex and livelier semen = male child
• Freud? Standard complex shit
• Saint Augustine? original sin, baby inherits wickedness from its father, transmitted by sex.
• Martin Luther? rather have a dead son than a disobedient one

Why better now?

Now is probably the best time ever to be a father, at least in rich countries. Many employers offer generous paternity leave; in much of Europe, they are required to. American dads do three times as much child care today as they did in the 1960s. The notion that it is unmanly to read bedtime stories is now hopelessly out of date: men are more likely than women to say they wish they saw more of the rugrats.

As Richard Reeves of the Brookings Institution observes in “Of Boys and Men”, dads are more likely to encourage openness to the world and a bit of risk-taking. Paternal involvement tends to reduce adolescent delinquency. Teenage girls who are close to their fathers exhibit better mental health as adults.

Class divide in parenting

The blessings of greater equality have come with a big caveat, however. Not all men have adapted well to the new world. Whereas college-educated dads in America are spending more time with their children, their less-educated peers are spending slightly less than they did 20 years ago. They are also far more likely to live apart from their kids and hardly see them at all. Many working-class men, meanwhile, are missing out entirely on the joys of fatherhood: now that women can afford to be pickier, more men are being left on the shelf. Many resent it intensely, and this has fed a politics of male grievance in much of the developed world.