Grey's Anatomy actress Katherine Heigl has ruled out having biological children, insisting she's "always planned to adopt". The 28-year-old's character in new movie Knocked Up has a gruesome birth scene, and labour is something Heigl is not keen to go through in real life. She says, "I've always planned to adopt anyway, but that definitely reinforced my want to. "I'm done with the whole idea of having my own children. (It) doesn't seem like any fun. I don't think it's necessary to go through all of that."