There are lots of things about Judd Apatow’s new comedy “This Is 40” that don’t add up. Some are annoying but negligible, like the movie’s asking us to believe that December in Los Angeles is a season for shorts and backyard pool parties. Others are annoying but par for the Hollywood course, like its asking us to believe that a couple with creative, unstable careers (like owning an indie record label and a clothing boutique) and no outside financial support can nonetheless drive a Lexus and a BMW, afford personal trainers, eastern healers, and therapists, and live in the kind of house (easily three million dollars, even in a down market) in which every room is a tasteful mélange of statement-piece furniture, imported rugs, fresh cut flowers, original art, and colorful, handcrafted children’s toys.

Some implausibilities, however, deserve some dissection. Let’s take those children. They are eight and thirteen. Their parents, Pete and Debbie, are turning forty. That means they had their first child at twenty-seven. You don’t see that very often in people with three million dollar houses, unconventional careers and no trust funds.

In reviewing “This Is 40,” most critics have largely ignored this socio-ecomomic conundrum, focussing instead on Pete and Debbie’s unchecked shallowness and immaturity, as well as the degree to which they’ve managed to combine cozy family life with salivary-gland-stimulating interior design. Not that any of that strains the limits of credulity. You will find as many children growing up in the luxury Spanish colonials of L.A.’s affluent west side neighborhoods as you will in the brownstones of Park Slope or the Queen Anne Victorians of San Francisco or Seattle. You will also find that their moms and dads were generally not having babies in their twenties, since acquiring that kind of real estate almost always means delaying childbearing (and in many cases marriage) in favor of building the careers that will pay for it.

When “This Is 40” hit theaters on December 21st, a conversation was already in progress surrounding Judith Shulevitz’s New Republic cover story “How Older Parenthood Will Upend American Society.” Working from a body of new research, as well as her own experience as a first-time mother at thirty-eight, Shulevitz wrote about the “natural experiment” of assisted-reproductive technologies and mounting evidence suggesting that older parents, even if they managed to conceive the old-fashioned way, run higher risks of producing children with sensory disorders, learning disabilities, and other kinds of developmental challenges.

Shulevitz got into the actuarial side of things, too. The greater the age gap between parent and child, the younger the child is likely to be when the parent dies. That has all sorts of implications. Grandparents may never get to know—or even meet—their grandchildren. Parents raising toddlers may find themselves dashing from the pre-school to the assisted-living center as they cope with the needs of their own aging parents. In the U.S., where in 2007 birthrates dipped below replacement levels for the first time since the mid nineteen-eighties, the only people having more babies than in the past are parents over forty.

The smaller families generated by today’s late starters means fewer workers and taxpayers tomorrow. This was the among the points made by New York Times columnist Ross Douthat, whose column “More Babies, Please” made for an effective opening act for Shulevitz’s article. “Relatively youthful populations speed economic growth and keep spending commitments affordable,” Douthat wrote, adding that declining fertility in Latin America means the U.S. can no longer look to Hispanic immigrants as a source of population growth.

Fair enough, but where Douthat really ticked people off was in his assertion that “the retreat from child rearing” is “a symptom of late-modern exhaustion” and “a spirit that privileges the present over the future.” The present over the future? For the educated classes whose reduced fecundity has Douthat so worried, it seems the opposite is true. People are too future oriented, too worried about feathering the nest before filling it, too damn responsible to have a baby while they’re still in school and using ironing boards as dining tables. Late starts are not the product of laziness but in fact of ambition—of wanting to meet educational goals and career demands and refusing to settle until you’ve absolutely, totally, definitely met the right person.

Readers of both articles shouted points like these from the rooftops. In blog posts, on comment boards and in phone calls to radio shows, people wrung their hands alongside Shulevitz and denounced Douthat as an antediluvian scold. But the more complicated subtext of the discussion was that in certain circles (particularly those in which you’re likely to find aspiring indie record producers) early marriage, and especially early childbearing, isn’t just a professional or social liability but a form of self-sabotage. “In my field, which is journalism,” Shulevitz said in an interview, “starting a family in your twenties sent a strong signal that you weren’t serious.” A commenter on The New Republic’s Web site recalled being pregnant at twenty-six and people being shocked that anyone would start a family before buying a house. “Many of our friends had a long list of conditions that had to be met before they had kids,” the commenter wrote. “Own a home, get tenure/partnership, have a certain amount of money in the bank.”

It’s not that “This Is 40” ignores the existence of older parents raising young children. On the contrary, it makes a cartoonish leitmotif of them, one we’re set up to pity and mock: a conspicuously gray-haired pregnant woman at the school dressed in a throwback, hippyish dress; Debbie’s cold, estranged father, who built a second family while neglecting her; Pete’s sixty-something father, whose wife-of-a-certain-age sought fertility treatments and wound up with triplets that have left them broke and living in a grim little ranch house under the flight path of L.A.X. These characters are supposed to reflect Shulevitz’s upended society, but they’re really examples of what she calls “gerontological voyeurism” or “doddering-parent porn,” an ugly reflection of the kinds of anxieties that both Shulevitz and DouthatÂ are writing about. Nowhere do we see the forty-somethings with toddlers that would likely make up Pete and Debbie’s social circle. Moreover, nowhere do we see the kinds of forty-somethings that really do start families at twenty-five, the ones whose early-in-life financial sacrifices mean they probably won’t be moving to Brentwood any time soon.

Apatow’s films are famous for their scatology (amply represented in “This Is 40”) and they can also be reliable vehicles for Hollywood fantasies about beauty, love, and the refusal to grow up. But in “This is 40,” Apatow seems to be really trying to say something profound about marriage and the difficulties of getting older. The problem is it’s almost as if he’s a fourteen-year-old imagining what it’s like to be forty (“that’s like, really old—but at least you can have nice cars!”) and the result is that the movie is a stunning misrepresentation of life at any stage. This is not the way we live now. These people are outliers.

Which actually makes perfect sense. Peter and Debbie are not characters, really, but versions of the real-life Mr. and Mrs. Apatow (Debbie is played by Leslie Mann, Apatow’s wife, and Sadie and Charlotte are played by their real daughters.) Mann and Apatow are now forty and forty-five, respectively. They had their first daughter, Maude, when they were twenty-five and thirty. Since Apatow was by then a successful writer and producer in Hollywood, there’s no reason to believe they weren’t already living in a three thousand square-foot post-and-beam and well into their second kitchen remodel. And though no one’s suggesting the movie should have been called “These are the Apatows at 40” (though that does have a promising, Pixar-like ring to it, as though it were a movie about squirrels suddenly faced with high cholesterol) the collectivist overtones of a title like “This Is 40” are singularly disingenuous. Because this isn’t forty. It’s more like fifty—for the one per cent.

Meghan Daum is an opinion columnist at The Los Angeles Times. Her most recent book is “Life Would Be Perfect If I Lived In That House”.