I take it back. There have been studies. Common sense and science are in line in this case. The amount of people who admit to operating outside of gender norms is <4% according to certain studies.

http://www.bloomberg.com/politics/articles/2015-05-22/americ...

>I don't like appeals to "common sense" in political matters

All things must often appeal to common sense regardless of the politics behind the issue. Males have penises and females don't, does a scientific study need to be conducted to prove this point? No. Because if we needed a scientific study for every possible issue without regard to common sense we would make zero progress on any topic.

> Males have penises and females don't, does a scientific study need to be conducted to prove this point?

What you've described is what I refer to as "sex" while totally ignoring the topic of gender. https://en.wikipedia.org/wiki/Sex_and_gender_distinction

I'm not sure what your politics are, but a lot of people who have traveled down this path in a conversation ended up expressing very intolerant opinions towards transgendered people. If you do feel contempt for someone whose gender identity and/or assumed gender role doesn't match their biological sex, please don't share that opinion with me.