I recall it taking me a few weeks to figure out if Yar/Justy was a guy or girl. Pretty sure I pegged the rest of you right away.

Wolf Kanno I always knew was a guy but I thought he was gay for a really long time because I could've sworn he said something about a boyfriend.

Semi-related if I had a nickel for the number of times people in chat/forum have said "Pike is a girl?!?" I would have a lot of nickels.