The tipping point is a generation away, assuming women’s economic power keeps rising as expected. But already, the trend is stunning enough that TIME made it the subject of its current cover.

“Almost 40% of working wives out-earn their husbands,” noted Liza Mundy, author of “The Richer Sex”–both the cover story and a new book that goes by the same title–at a breakfast in New York City, hosted by TIME and Fortune.

The audience was Fortune’s Most Powerful Women: female Masters of the Universe who have seven-figure salaries and househusbands. Mundy’s research shows that women are out-earning men all around. In most U.S. metro areas, for instance, single childless women in their 20s have higher median incomes than their male peers. In Dallas and Atlanta, the average young woman earns $1.18 and $1.14, respectively, for every dollar earned by a male.

Why such rapid advancement? The Pill, Mundy said, helped spark the trend 50 years ago: Newly able to delay marriage and childbearing, women began focusing on their careers. America’s shift to a service economy also favors college grads, who increasingly tend to be female. Today, women make up 60% of U.S. college classes and earn more masters and doctorate degrees than men.

What can stop women from out-earning men in more than 50% of U.S. households? “Nothing that I can see,” Mundy, who writes for the Washington Post , told TIME Executive Editor Nancy Gibbs at the breakfast. Some industries, such as veterinary medicine, are so populated with women that few men are now entering them, she said. She calls the phenomenon “gender pollution.” In 25 years, law and medicine may well be female-dominated.

And there’s the fact that 41% of babies in the U.S. today are born to single mothers. While Mundy found no reliable data on how many of these unmarried moms are cohabiting vs. living alone, “what we do know from the census is that currently about 25% of children under 18 live with a mother and not a father.”

This got me and the powerful women at my breakfast table asking: Can men, bred to be providers, live happily in a world where women may not need them for support? An optimist, Mundy believes that many men will cede control as breadwinners.(One bit of evidence: Marriage rates for high-income women are rising, as overall marriage rates decline.) Moreover, society will adapt by “broadening the definition of masculinity,” she contends. Masculinity will include cooking as well as hunting, and child care as well as golf.

“We are always too quick to think masculinity is finished,” Mundy writes in her TIME cover story. If the evolution plays out as she hopes, both men and women will become richer in their own ways.

Click here to read why men are attracted to high-earning women.