I think that is an erroneous statement. I just read a short while back an article from a biologist the said a doe can birth fawns from two different bucks at the same time. Iwill have to search for the article, I don't remember exactly where I read it because I read everything about deer that goes past me. When in heat a doe will stand for breeding multiple times and more than one buck often will mount her. Their reproductive system is configured in such a way that individual eggs can be fertilized by separate bucks. This is a survival tactic to ensure that breeding will take place one way or another. Dang, I just read that! What a coincidence this would come up.