Well the answer in my case is yes... I have two rats that i bought within a week of each other. One is a black fur and the other is hairless. When i bought them they were both males and i know this because of the rat sack they were dragging around. Well i came home after work today and heard something that sounded like baby mice or rats in this case, so i was looking in the cage but could not see any babies and i thought i was just going insane or the rats were just making noise. I kept hearing it though so i moved the igloo again and after about a minute i saw the bedding move and after removing the layer their are 5-6 babies.. I was like WTF!!! And the black rat still has his jewls but the hairless rat does not..
I personally have never seen anything like this, i have had these rats for 4 months now and this just barely happened. I know frogs can change gender but not in anything else that ive ever heard.

So if anyone needs snake food soon, im the man to talk to...