There’s only one problem: none of this is proven. In the February issue of the Journal of Marriage and Family, Judith Stacey, a professor of sociology at New York University, and Timothy Biblarz, a demographer from the University of Southern California, consolidated the available data on the role of gender in child rearing. As Stacey and Biblarz point out, our ideas of what dads do and provide are based primarily on contrasts between married-couple parents and single-female parents: an apples-to-oranges exercise that conflates gender, sexual orientation, marital status, and biogenetic relationships in ways that a true comparison of parent gender—one that compared married gay-male couples or married lesbian couples to married heterosexuals, or single fathers to single mothers—would not. Most of the data fail to distinguish between a father and the income a father provides, or between the presence of a father and the presence of a second parent, regardless of gender.

Drawing on reliable comparative studies, you could say this: single moms tend to be more involved, set more rules, communicate better, and feel closer to their children than single dads. They have less difficulty monitoring their children’s whereabouts, friendships, and school progress. Their children do better on standardized tests and have higher grades, and teenagers of single moms are actually less likely to engage in delinquent behavior or substance abuse than those of single dads. Go, Murphy Brown.

The quality of parenting, Biblarz and Stacey say, is what really matters, not gender. But the real challenge to our notion of the “essential” father might well be the lesbian mom. On average, lesbian parents spend more time with their children than fathers do. They rate disputes with their children as less frequent than do hetero couples, and describe co-parenting more compatibly and with greater satisfaction. Their kids perceive their parents to be more available and dependable than do the children of heteros. They also discuss more emotional issues with their parents. They have fewer behavioral problems, and show more interest in and try harder at school.

According to Stacey and Biblarz, “Two women who chose to become parents together seemed to provide a double dose of a middle-class ‘feminine’ approach to parenting.” And, they conclude, “based strictly on the published science, one could argue that two women parent better on average than a woman and a man, or at least than a woman and man with a traditional division of family labor.”

Ah, there’s the rub. All howling to the contrary, most heterosexual men and women like that traditional division. Sticking to “gendered” parenting roles offers a seductive affirmation. Fathers, roughhouse all you want. But we, gatekeeper moms, are in charge of the rest. We could give you detailed instruction, and you still couldn’t possibly do it as well. “Even women who want their husbands to help more with the kids don’t want to give up their traditional authority,” says Stephanie Coontz, director of research at the Council on Contemporary Families. In addition to our pragmatic embrace of these roles, we still live in a culture with a deeply embedded notion of what a father is, beyond just another set of hands, and men, women, and children cling to it.

The bad news for Dad is that despite common perception, there’s nothing objectively essential about his contribution. The good news is, we’ve gotten used to him.