Thomas Beatie of Bend, is unusual in several ways. For one thing, he was born a woman but later decided to become a man. Over the years Beatie had various surgeries and hormone therapies, but retained his ovaries and uterus, and that is the reason that a “man” could become pregnant. If Beatie has retained his baby-making equipment, then he is in fact still biologically a woman, not a man.

Source – http://www.livescience.com/2409-pregnant-man-real-hoax.html