Adam,
I am a female nurse I am currently in OB (not too many male nurses there), but before I did OB I did Open heart recovery (CVICU) and CCU. I found that there were many male nurses in both of those departments also many CRNA's are men. I feel that they are such a value to nursing, just as male teachers are to teaching. Please keep your chin up and don't give up. This "Teacher" is a moron. When you get out I think you will find your female collegues will be very happy to work with you. I am still very close friends with several of the male nurses I worked with when I first got out of school. I also would like to say I commend you for going to school as a single parent. I know it is tough but worth it. I am a single parent of teenagers and the greatest thing about nursing is the flexibility to work the kind of hours that you can be home more. They grow so fast !! Take care of yourself and I will be sending you positive vibes.