Seth Rogen has shared his understanding of why Anne Hathaway originally cast in the 2007 comedy Knocked Up ultimately exited the project, leading to Katherine Heigl taking the role. Rogen recounted the situation on The A24 Podcast, stating that Hathaway's departure stemmed from her discomfort with the film's depiction of childbirth.
According to Rogen's recollection, Hathaway expressed that she did not want the "crowning" scene, which visually represents the moment a baby emerges during birth, to be part of the film. "She didn’t want the crowning of the baby to be visually representative, which I respect," Rogen said. He elaborated that while rehearsals had begun, Hathaway's decision was clear and accepted. "There was no confusion. After it happened in the movie no-one was like... because it was a baby coming out of it."
Hathaway herself has previously spoken about her reasons for leaving the film. In a 2008 interview with Marie Claire, she stated that she turned down the part because the script was going to show a vagina – not hers, but that of another actress – and she did not believe it was necessary for the story. This aligns with Rogen's account, which suggests Hathaway's concern was about the visual element of childbirth rather than personal nudity.
Rogen acknowledged Hathaway's foresight, noting that "history will tell… she has been right about a lot more things than I have over the years! So I think she was probably right. She knew what was right for her, yes. And then Heigl was great. Katie Heigl was great.” Heigl ultimately portrayed Alison Scott, the character Hathaway was initially slated to play, a journalist who becomes pregnant after a one-night stand with Rogen's character.