Fathers
Worldwide, 10% to 40% of children grow up in households with no father. In the U.S., more than half of divorced fathers lose contact with their kids within a few years. By the end of 10 years, as many as two-thirds of them have drifted out of their children’s lives. According to a 1994 study by the Children’s Defense Fund, men are more likely to default on a child-support payment (49%) than a used-car payment (3%). In intact U.S. families, fathers spend an average of less than an hour a day (up from 20 minutes a few decades ago) focussed on their children.
Homo sapiens produces the most slowly maturing young of all mammals. Among foraging humans, children need 19 years — and consume 13 million calories — before producing more food for their community than they take from it, according to Hillard Kaplan. There is more variation in fathering styles across human cultures than in any other primate species.
One thing that draws a human male to a child of his is that, hormonally speaking, men are similar to women, during the period approaching a child’s birth and its infancy. As in some other mammalian species, human males have high levels of prolactin (a hormone usually associated with lactating mothers) toward the end of a partner’s pregnancy.
Katherine Wynne-Edwards and Anne Storey have shown that new or expectant fathers holding either their baby or a doll wrapped in a blanket that recently held — and still smells of — a newborn experienced a rise in prolactin and cortisol (a stress hormone associated with mothering) and a drop in testosterone. When the men listened to a tape of a crying newborn and were shown a videotape of a newborn struggling to nurse, the ones who reported the greatest urge to comfort the baby were the ones whose hormone levels had changed the most.
Dads have to spend time close to babies for hormones to kick in.
In traditional societies, 40% of offspring might die before age 5.
Among some West African Mandinka, the help of a maternal grandmother has been linked with a halving of the under-5 mortality rate. Similar benefits were shown in Finnish farming communities in the 18th century.
It was this cooperative system that allowed mothers to have more babies than they could support and fathers to vary in how they cared for them.