Junior

Junior is a movie starring Arnold Schwarzenegger, Danny DeVito, and Emma Thompson. As part of a fertility research project, a male scientist agrees to carry a pregnancy in his own body.
A research scientist becomes the world's first pregnant man in order to test a drug he and a colleague have designed for expectant women. To carry out the trial, he has an embryo implant, believing that he will only carry the baby for three months – hardly expecting to face the prospect of giving birth.