And the films have made that case both despite and with the help of their plots’ occasional reliance on poop and pot and penises. “By marrying raunch and moralism,” the conservative columnist Ross Douthat noted in 2009, “Apatow’s movies have done the near impossible: They’ve made an effectively conservative message about relationships and reproduction seem relatable, funny, down-to-earth and even sexy.”

It’s a fair observation. And it’s not at all, necessarily, a bad thing.

But it is not, however, the whole thing. Because when it comes to Apatovian atavism, there’s another way—a bigger way— in which The 40-Year-Old Virgin and the genre that it helped to spawn are conservative. And it has less to do with cultural conservatism and more to do with something even more basic: the way we think about adulthood. The way we distinguish between children and—another movie of the genre—grown-ups.

What makes someone an adult? Turning 21? Graduating from high school? Trading in a Craigslisted IKEA coffee table for a brand-new IKEA coffee table? The benchmarks vary, tantalizingly and frustratingly. What is clear, though—and what The 40-Year-Old Virgin makes especially clear—is that whatever makes an adult now, it isn’t, in general, the thing that has defined adulthood for so much of human history: the having of sex. Nor is it the simple attainment of a certain age, be it 18 or 21 or 40. Andy, a 40-year-old who collects action figures and rides a bike to work, is a grown man who isn’t fully an adult—who is trapped, by circumstance and by choice, within a kind of self-imposed arrested development.

The other characters, too, are stunted. There’s Jay (Romany Malco), who, despite having a girlfriend, treats women as conquests, immature-man-style. There’s David (Paul Rudd), who adopts most of the character conceits—crying, obsession, longing—of a teenage girl. There’s his ex, Amy (Mindy Kaling), who adopts the conceits of a teenage boy. They’re all trying—and, largely, failing—to navigate what “growing up” means in an age that finds adulthood to be an extremely nebulous proposition. The 40-Year-Old Virgin, “sex comedy” aside, isn’t (just) about sex. It’s about the loss of the cultural infrastructures that sex used to symbolize: the tidy divisions of youth from all that comes after it. The rituals and habits and assumptions that used to make adulthood a nearly foregone conclusion.

* * *

It’s a common complaint, in cultural criticism, that adulthood has—in some figurative way, and maybe even totally literally—died. The Puer Aeternus. The Bobo. The Grup. As A.O. Scott claimed last year, “Nobody knows how to be a grown-up anymore. Adulthood as we have known it has become conceptually untenable.” Which is proximate to another argument, one that was made many times before Judd Apatow came along: that adulthood hasn’t so much passed away as it’s been flattened and dispersed and Peter Panned. Young people—via a hypersexualized media culture, via the varying pressures toward economic and social and academic achievement—have been forced to grow up prematurely. Adulthood, meanwhile, has been youth-enized by people in their 20s and 30s choosing work/friends/Netflix/financial self-sufficiency over traditional markers of grown-up-ness: marriage, kids, home-ownership, etc.