Hello Adam,
Gender discrimination is a reality both in nursing school and the field depending on where you work. Sometimes it is subtle, sometimes it is blatant. We have discussed it on another thread here:
http://www.nursingdiscussions.com/gender
If this professor gives you a hard time about the missing a class issue, I'd be ready to appeal it and give specific examples of other students that are being treated more leniently.
You might want to bring the issue to the attention of the Dean privately. Tell her this has become an issue and before it escalates further, you want to tell her exactly what the situation is.
Are there other guys in your classes or the school? Would be interesting to see if they've had similar experiences.
Keep in mind also, that nursing instructors can be notoriously harsh on students, even when there is no apparent need or reason for it.
It's part of the "nursing school" experience where they try to weed out as many "unfit" nurses as they can.
Don't take it too personally, but to don't let yourself be abused either.
Andrew Lopez, RN
http://www.4nursingstudents.com