That goes for the bedroom as well. If you thought today’s “hookup” culture was run by young testosterone-charged men who want sex and no commitment, think again. Rosin insists that women are often in charge and the primary beneficiaries. A steady relationship with a guy, as one researcher puts it, is like adding an extra course to an already full load. Who needs it? These women have “hearts of steel,” and the hookup culture gives them sex without getting in the way of ­career-building. Yet Rosin’s interviews with these young women are at times heartbreaking; they really do want love in their lives.

Hookups notwithstanding, college-­educated men and women are more likely to marry and less likely to divorce. And although women still do a majority of the child care, men are changing, Rosin says; they are becoming, well, more like women: flexi-, plastic men willing — wanting — to share in domestic life. Some workplaces are changing too, and some women are finding more ways to work and have children. Everyone is happier.

Except, of course, that everyone is not — or not quite. Rosin’s chapter on women at “the top” indulges the soul-searching of educated women trying to “have it all.” She gives us Silicon Valley as today’s mecca, insisting that companies like Google and Facebook — flexible, new-economy places — are (in spite of their notorious frat-house cultures) solving the problems of women and children and work. But while I’m happy to learn that a woman at Google persuaded her boss to fly her child and her nanny with her around the world business class, this hardly seems a viable economic model for most companies, or most mothers.

And what about Rosin’s faith in the adage that for women to make it to the top, you need to get women like Sheryl Sandberg, the chief operating officer of Facebook, to the top so that they can “remake the workplace in their own image”? Sandberg aside, we know this doesn’t necessarily work: women aren’t always, or even usually, looking out for other women — or even being nice to them. Many prefer to work with men; and some are willing to put in the long hours it takes to wrest their way up the chain of command.

In the end, there is something smug — and wrong — about Rosin’s depiction of “Plastic Woman.” Is it really a good idea to say that we are, by gender if not by sex, open, empathic, flexible, patient, prone to communal problem-solving and the like? We’ve known for a long time that men do not hold a monopoly on being rigid, hierarchical, close-minded or authoritarian. Yet the women in this book are almost all organized go-getters, whereas the men come across as lazy, unambitious couch potatoes.

It is hard not to cringe when Rosin compares a Type A girl who sits still in school and makes pages of to-do lists every night with a sloppier but equally high-­performing boy who can barely remember what comes next in his day. Rosin holds the girl (her daughter) up to the light and suggests that the boy (her son) will need to find his own “inner secretary” if he is to succeed in the world we live in. Well, maybe, but everything in me wants to defend the boy for just being who he is. Do we really want an alpha-girl model, even if she does succeed in the new world economy, whatever that is? Do we want a model at all? Why should a son — or anyone, for that matter — want to be more like anyone else (much less his sister — or mother)?

Above all, is it really a good idea to suggest that women are poised to inherit the economy and that over time men and boys, God bless them, may learn to adjust and become more — more what? More like us (except when we’re not)? To suggest, in other words, that success — material, social, sexual, emotional — depends on (our!) gender traits and not on the legal and institutional frameworks we live in? I’m all for each of us remaking ourselves from within, but this kind of argument seems carelessly apolitical, especially at a moment when we are faced with public officials actively working to undermine access to birth control, abortion, equal pay for equal work. Talk about endings.

And I can’t share Rosin’s rosy faith in the global economy. Revolutions, economic or otherwise, have a way of disappointing women. They tear down the old, women step in and make strides, and as a new order sets in the strides disappear. Are Rosin’s Plastic Women genuine victors, or are they — or will they become — unwitting victims? Will the women who are so diligently training themselves as pharmacists today be as flexible and confident when the winds of the feckless global economy turn against them? How flexible can a woman be when she has been training for something for years and suddenly it is blown off the map by the “new” economy? Ask the men who are ended.