[Despanan]

I think not asking a gender is more about the fact that such questions are often considered to be extremely rude, especially when they're directed at a stranger, rather than laziness.

I mean, just sayin' my friend's kid is Female->Male trans. His parents kept searching for a school, and finally found one when another kid said: "So, are you a boy or a girl?" an a second student reprimanded him with "That's not an appropriate question!"

Granted, things are different between adults, but it's not always so cut and dry. For good or ill, there are serious social taboos about asking a person's gender, and you rarely know how they're going to take it.