Marcus--to get back to the questions you asked:
Yes, it is statistically unusual for guys to go to nursing school
. The percentage of guys who go into nursing as compared to guys going into MANY other vocational fields is VERY low.
On the other side of the coin, it is also statistically unusual for nuring students to be guys, less than 8% instead of the 50% that would be statistically expected, and more than half of us quit the nursing field within 5 years of graduation. (There is a thread to this effect in this very forum.)
Yes, male nurses are often called "doctor," and it is wise to politely correct those who make this small mistake, if they are coherent enough for the correction to make a dent, for legal reasons as well as for social ones. It is an honest and understandable mistake, after all, and certainly nothing to get huffy about. Just as we might call a female patient "Mrs. so-and-so," when the title is more accurately "Miss so-and-so." (Though hopefully we would be too tactful to ask "Why aren't you married?" in such an event.)
IN MY EXPERIENCE at 8 or 9 jobs as well as in nursing school, about half of us male nurses are gay, though this is ordinarly not an issue (except when we are in the military and need to keep it a secret, even from people like Esther who might not personally object).