David Denby wrote a marvelous, if slightly wistful, essay in the New Yorker over the summer in which he wondered, "How did we get from Frank Capra's `It Happened One Night' (1934) to Judd Aptow's `Knocked Up' (2007)"?

How, indeed. A complete answer would produce a massive cultural history of the past 73 years. Instead,  Denby chooses to  crystallize the salient differences in romantic comedy, then and now. In olden days--looking back 73 years to "It Happened One NIght" is looking back to olden days--the hero and heroines competed as equals. Discussing such movies as "Bringing Up Baby," "The Lady Eve," "Easy Living," "Midnight" among others, Denby points out: "The man and woman may not enjoy parity of social standing or money, bu they are equals in spirit, will, and body."

Despite the sexual revolution, feminism, and the rise of the New Man (or, perhaps, because of them), this is not at all the case in the new riffs on the old genre. Today, the most important relationships in  what we persist in calling romantic comedy tend to be among the boy-buddies, not the girl. In such movies as "High Fidelity," "Wedding Crashers," and this summer's big hit,   "Knocked Up," Denby notes that the heroine, aside from a marked careerism, "doesn't have an idea in her head, and she's not the one who makes the jokes." 

And what jokes. "Knocked Up" first came to my own attention in a preview I had to endure, squirming, while awaiting a showing of  "Miss Potter" with my daughters. It's one long hoot about a pregnancy contrived between a career girl (no jokes) and a wastrel (lots of jokes)--a slacker-striver romance, as Denby calls the genre. An admirer of "Knocked Up's" director, Denby  goes on to write: "I wonder if Apatow, like his funny youths, shouldn't move on. It seems strange to complain of repetition when a director does something particularly well, and Apatow does the infantilism of the male bond better than anyone, but I'd be quite happy if I never saw another bong-gurgling slacker or male pack again." He continues: "The society that produced Katherine Hepburn and Carole Lombard movies has vanished; manners, in the sense of elegance, have disappeared. But manners as spiritual style are more important than ever, and Apatow has demonstrated that he knows this as well as anyone. So how can he not know that the key to making a great romantic comedy is to create heroines equal in wit to men? They don't have to dress for dinner, but they should challenge the men intellectually and spiritually, rather than simply offering their bodies as a way of dragging the clods out of their adolescent stupor."

Of course, maybe offering  bodies has become all that we post-1960s generations understand, with the comedy of it all depending on what shock value remains potent.     

At least, temporarily.  Already, the shock value of the "Knocked Up" title is  gone, just  a few months after its release.

So no wonder when this fall brings us another picture along similar lines (only more so) eyebrows fail to lift altogether.  I am referring to the enthusiastically received comedy "Juno," which is about a teenaged girl (not an adult as in other pregnancy comedies) becomes pregnant by her reluctant boyfriend (what else?).

Yuks  abound, reviewers say,  in the "comedic" situations created by the 16-year-old  heroine enquiring about an abortion (she doesn't get one), and by her and her father  visiting a childless couple who plan to adopt the baby. As an example, the Washington Post recounts:  "`I'd like to procure a hasty abortion,' she says with an ironic jovial tone when she calls that clinic."

Ironic? Jovial? Guess you had to be there--and, admittedly, I haven't and may not ever be. What intrigues me most--morbid curiosity--is the failure of  a movie, rated PG-13, that plays teen pregnancy for laughs (check out the poster) to get a rise, a shock, even a second look, from  society.

Me, I'll take (and recommend) "Bachelor Mother" (1939) with Ginger  Rogers.