To paraphrase P.T. Barnum, nobody ever went broke underestimating the maturity of the American male. On the contrary, as the films of Judd Apatow and magazines like Maxim make clear, immaturity among 20- and 30-something guys is a reliable cash source. It’s a phenomenon on which nearly everyone can agree: At least among middle-class American men, adolescence now stretches deep into age brackets that just a couple of generations ago were considered fully adult. The demographic, economic, and social causes and consequences are up for debate, however, and in “Manning Up,’’ author Kay S. Hymowitz argues vigorously, if wrong-headedly, that most of the blame can be laid upon the women’s movement.

In describing the problem of these boyish men, Hymowitz starts by laying out the terms others have used to label these not-quite-grown-ups, from “quarterlife’’ to “adultescence’’ to the wonderfully awful “twixters.’’ The term she uses is preadult. Preadulthood, she argues, “has . . . confounded the primordial source for a mate. It has delayed a stable sense of identity, dramatically expanded the pool of possible spouses, mystified courtship routines, and helped to throw into doubt the very meaning of marriage.’’ All of which has led, she points out, to a lot of frustrated and confused women, who wonder why they can’t find a reasonably grown-up man to date, one who isn’t married already — to his video-game controller and beer bong.

Hymowitz, a scholar at the right-leaning Manhattan Institute, can be hilarious (“Here’s a cultural mystery for you: Adam Sandler’’), but too often her cleverness is drenched in a bitter, or even bizarre, reading of modern feminism. She writes of a hypothetical man who is confused about how chivalrous to be on a date because he’s been “chewed out by a female colleague’’ for holding open an office door, and who feels unnecessary to members of “the vibrator-powered womanhood of today.’’ Her zeal to somehow tie women’s educational and economic advances to this perceived downward spiral in men’s maturity levels leads her to make wild claims (“Women’s determination to achieve financial independence before marriage is something very new, and is at the heart of preadulthood.’’) and to confuse cause and effect, as when she points out that women only make less money than men if you take into account their disproportional numbers in low-paying careers — there’s a more logical way to spin that fact, as I’m sure she realizes. But when your point is that somehow women are doing better than men, and that this improvement in women’s lives somehow comes at the expense of men’s identity, well, it’s better to throw around lines like “feminism’s siren call to the workplace’’ than to question why jobs traditionally held by women pay less than jobs traditionally held by men.

Hymowitz isn’t afraid to contradict herself, which can be confusing. Are preadult child-men hapless losers, shut out of the job market by the rampaging hordes of alpha girls who have not only taken their fair share of jobs but also somehow reshaped the entire American economy? Yes. But at the same time they are doing OK, able to devote more of their working years to career-building (while women often have to take time off to bear and raise kids), and at the same time free to delay marriage and parenthood decades past when women can. Whether we are to pity, condemn, or envy the child-man is never entirely clear. What is clear is that feminism (in Hymowitz’s view, a force that puts Women’s Centers in colleges that lack, tragically, matching Men’s Centers) is somehow to blame. As for the child-man, happily taking the slow road to adulthood, maybe his failure to “man up’’ is less feminism’s fault than the culture’s willingness to indulge him.

Kate Tuttle, a writer and editor, can be reached at kate.tuttle@gmail.com.

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