Ezra Klein on Knocked Up:
The flick is pro-choice in the most literal sense of the term. Katherine Heigl's character receives advice in both directions, and then makes a decision -- a decision the audience may very well conclude is the wrong one. But she has a choice; nothing is forced on her, and the most explicit scene on abortion features an eloquent speech by her mother advising her to end the pregnancy because, at this point, she's not ready, and these are not the right circumstances. Heigl, it turns out, disagrees, but that's a perfectly allowable, and indeed respectable, decision within the choice framework.
Which just goes to show you, I guess, that the preconceptions you carry into a movie make all the difference in the world. Ezra, who's of course pro-choice, watched a mother urge her daughter to "take care of it - just take care of it!" so that someday she can have "a real baby," and saw an "eloquent" statement of the pro-abortion position. I saw a mother who seemed to exist only to make the pro-choice side look deeply unpleasant: She was the embodiment of the uptight, respectability-uber-alles, Rockefeller Republican WASP, dropping into a movie whose genre is deeply inhospitable to that type - and moreover, she never showed up again in the film (not even at the birth), save for a cameo during the closing credits, apparently leaving Katherine Heigl's character to fend for herself once she declined to "take care of it."
But maybe Ezra has it right, and I was just looking at the thing through choose-life-colored glasses.