This quote from A.O. Scott's review of Juno in The New York Times really bothers me,
"Juno" also shares with "Knocked Up" an underlying theme, a message that is not anti-abortion but rather pro-adulthood. It follows its heroine - and by the end she has earned that title - on a twisty path toward responsibility and greater self-understanding.
http://movies.nytimes.com/2007/12/05/movies/05juno.html