The tawdry female bosses are tiresome, and we could do with more male fanservice.

[Eldevern]

...

Not totally true. If you learn to draw, you will fast realize that to draw someone who look to be a girl/women or someone who look the be a man will share some specific shape rules based on "biological gender" (as an average).

Head skeleton of a woman and head skeleton of a man can be identified as such. You can know if it is a woman or a man based of the width of the pelvis. So no, it is not cultural or education, a part is purely genetical since humans, as any mammal has genetical inherited reproduction criterias.