Children have started to discuss with eachother if I'm boy or girl for years now.
And it actually always ends up in them saying I'm a boy, 'because of my shoes'. So yes, wear male shoes and you will pass as male for children. I do anyway.

(the kid really ended the discussion with saying like, "No look, it's a boy, he's got boy shoes")
Hah, I once had these two rather young children shout to eachother because the girl was so sure I was a girl and the boy was so sure I was a boy. I was cycling past and I could still hear them while I was well on my way down the street.. "No it's a boy!""No it's a girl!""Nooo, it's a boy!"

I don't know, I feel like I pass when nobody looks up if I'm using the toilet and if I'm 'sir'd while buying stuff.