Ever since I started growing my hair out...about 7? years ago?? people have mam'd me. I'm not sure why. Just started the pills last month, still dress in guy clothes (except for my pants), and my voice is very deep. The kind of deep that women find it soothing, so I've been told. At the time it was embarrassing (especially in the accompaniment of my mom or dad, though of course then "mam" wouldn't be used, some other pronoun). Now I'm used to it. I'll turn my head and look if someone calls out a feminine caller and I think they want to talk to me or something.
I've stopped going to public bathrooms as much as possible. Getting weird looks is something I haven't quite gotten over yet. In university, I've had many a boy leave the bathroom as I was washing my hands and come back in. So I started using the few family bathrooms in the schol at the time. Still happens now when there's not another guy in there with me. Unfortunately Korea has no such thing as family bathrooms, so I've been holding it when I can.
2 years ago when I was attending language school, another foreigner (someone from south asia, I think) asked me bluntly "are you a girl? I can't tell." ..Now, my thinking is, why wouldn't you just ask something like, "Where are you from? How are you? or something simple to figure it out for yourself by using ears? 1 classmate at the time (first day of class) from Cambodia saw me, thought I was girl, said hi, and when I replied....very surprised. Said it was because long haired guys don't exist where she's from.
Speaking of baths...a friend of mine kept me out late at night 1 time so we were forced to sleep in a sort of bath house, which if you don't know are segregated (hated it, not my cup of tea). When we checked in, the staff there double checked to make sure I was really a guy (I had to say something as evidence) and all the guys at some point stared for more than 3 seconds at me. If not 3, I could feel it/saw it for a long time. Some looked more than 5 times. 1 of the male staffers finally said something to me when I checked out saying something like "you look like a girl, I was so confused." --I totally disagree with his comment, but thank you anyway.

Said friend also has me meet his friends. Many of his female friends say "oh, I thought you were a girl" upon meeting me (what a nice greeting...). Too bad my voice and bone structure disagrees.