And I thought asking us to accept a 40-year-old virgin was pushing it: "Knocked Up"

Yes, another Apatow movie. This guy is putting them out every few months now, right? Looks like the cancellation of "Freaks and Geeks" really set him back.

When I saw the trailer for this movie about a one-night stand that results in a pregnancy and then courtship, I was initially on board. Seth Rogen? He's goofy. Katherine Heigl? She's hot. And hey, Paul Rudd! In a supporting role with good lines! We love Paul Rudd!

Then came the reviews, which were overwhelmingly positive. Good thing, no? I guess, but it gave me pause. What if the guy who was spot-on with "The 40-Year-Old Virgin" was now too mainstream? What if the locker-room humor deftly combined with genuine sweetness -- plus some truly funny scenes -- from that movie gave way to more traditional stuff here? What if we didn't get to see Heigl's boobs?

Our story: Rogen is a loser trying to set up a semi-porn website with his loser pals. Heigl works for E! and has just been promoted to an on-air role. Let's celebrate with our older, married sister! Let's get drunk! Let's have sex with this chubby, hairy guy we just met in a bar! It's not like I'll get pregnant, right? Actually, it's not enitrely her fault, and these crazy kids -- despite learning in the light of day that they have virtually nothing in commom but an embryo -- decide to give the relationship a try. We all know what happens next. Yep ... hijinks ensue.

Plenty of funny stuff here. Rogen shlubs around trying to balance the idea of dating with his regular pastimes of smoking weed and being broke. Heigl gets hormonal and understandably p!ssed at her would-be boyfriend and actual child's father. Her sister, played by Leslie Mann, looks on disparagingly while arguing with her own husband, the incomparable Mr. Rudd. Rogen and Rudd bond. Rogen's friends -- foremost among them the hilariously creepy Jason Segal -- provide comic relief. And so on and so forth.

(One surprise: Ryan Seacrest can do funny. Of course, he lampoons himself. Makes sense when you think of it that way.)

Those things, plus the fact that much of the dialogue is improvised or close to it, make it easy to watch and laugh at "Knocked Up," which is more funny than not. It's also longer than it needs to be -- more than two hours regardless of whether you watch the theater or unrated version. That's too long for this kind of thing, no matter how clever it is.

Two other issues:

1. Some dialogue got a little too cute and forced at times. I liked a lot of the pop culture references -- "You're going to be embarrassed when you realize I'm Wilmer Valderrama!" -- but thought they could have let up a bit. "Superbad" was better on this count. Then again, those guys really were kids instead of twentysomething losers.

2. The overall premise -- that Heigl would (a) not abort and (b) try to date Rogen -- is farfetched to say the least. I can see her keeping it, sure; even with her new TV gig and career taking off, she still could have the baby. Totally makes sense. But staying with Rogen, especially after multiple pieces of evidence pointing to his inadequacy as a mate and father, is asking a lot of the audience.

But hey, don't get me wrong ... I was rooting for the guy. I've liked Heigl since "Under Siege 2" and "My Father, the Hero." Can't blame any loser for hitching his wagon to that star.