When we say Prophet, if we mean that high level of humanity it was and it is possible even for women to be Prophet, to receive message from Allah at least for herself.
But Prophet as a person who receives message from Allah and send it to people :
1. It is not easy to prove that all Messengers were men, as we do not know all of them.
2. (if we accept that all of them were men) It was a hard job that according to situations of that time it was not proper for women.
3. According to understanding of some scholars from Quran, saint Mary was a Prophet! So even women could be Messengers.