I don't always like David Denby, to say the least, but this essay raises a lot of good questions. Here's a snippet:
“Knocked Up” ... feels like one of the key movies of the era—a raw, discordant equivalent of “The Graduate” forty years ago. I’ve seen it with audiences in their twenties and thirties, and the excitement in the theatres is palpable—the audience is with the movie all the way, and, afterward, many of the young men (though not always the young women) say that it’s not only funny but true. They feel that way, I think, because the picture is unruly and surprising; it’s filled with the messes and rages of life in 2007 ....
Authentic as Ben and Alison seem to younger audiences, they are, like all the slacker-striver couples, strangers to anyone with a long memory of romantic comedy. Buster Keaton certainly played idle young swells in some of his silent movies, but, first humiliated and then challenged, he would exert himself to heroic effort to win the girl. In the end, he proved himself a lover. In the nineteen-thirties, the young, lean James Stewart projected a vulnerability that was immensely appealing. So did Jack Lemmon, in his frenetic way, in the fifties. In succeeding decades, Elliott Gould, George Segal, Alan Alda, and other actors played soulful types. Yet all these men wanted something. It’s hard to think of earlier heroes who were absolutely free of the desire to make an impression on the world and still got the girl. And the women in the old romantic comedies were daffy or tough or high-spirited or even spiritual in some way, but they were never blank. What’s going on in this new genre? “Knocked Up,” a raucously funny and explicit movie, has some dark corners, some fear and anxiety festering under the jokes. Apatow takes the slacker-striver romance to a place no one thought it would go. He also makes it clear, if we hadn’t noticed before, how drastically the entire genre breaks with the classic patterns of romantic comedy.
The sharpest critique of Apatow's movie that I've heard came from a woman I know, who argued that the debate about abortion is somewhat beside the point: The film's central implausibility isn't that Katherine Heigl's Alison would keep the child, but that she would keep the man. I think most people would agree that the leads' never-quite-resolved mismatch is, as Denby puts it later in his essay, "the weakest element in the movie"; the question is whether it's something to be forgiven with a laugh or endured with a shudder. I forgave it and laughed my way through the movie, but then again I'm a man; my friend was one of those less-amused young women Denby has in mind, and she argued (persuasively) that you could easily read Knocked Up as a film about the awful things that a woman will accept to ease the terrible vulnerability of pregnancy. Only a deep, unsettling and not-at-all-funny desperation, in her view, could explain why Alison would accept as a boyfriend (and presumably a husband) a man as gross, insensitive, underemployed and immature as Seth Rogen's Ben - a guy, she pointed out, who goes on a profane rant in a crowded restaurant when Alison tells him that she's pregnant, tries to beg a blowjob from her on their second date, invites her over to fast-forward through porn movies to help him get his dot-com smut empire off the ground, abandons her to rescue his bong during an earthquake, and so on and so forth, with precious few romantic gestures thrown in to mitigate his blundering. (He gets a job, eventually reads some baby books, and ... that's about it.) His rants are funny, sure, and he's basically good-hearted, but would you want your daughter to marry him? Or more aptly, would you want your daughter to be so freaked out by her pregnancy that she felt like she had to make it work with him?
I'm still turning over these questions in my mind.