I don't draw, so I can say for certain, but when I read the work of a comic book artist for a while and I see their picture, I get the impression they always draw faces in a way that resembles their own. As an example, Sara Pichelli has this characteristic nose that is totally hers.
I think there's truth to this statement. I guess, if you follow your gut, you end up doing what is more fun for you to draw / what you think is cool. Subconscious kinks can totally be a part of it.
(also, a manga in joke, but I hear people joking about how since Eichiro Oda, the One Piece dude, married his wife, a famous cosplayer, he amped up the fan service in his girls and each one looks the same... the same as his wife. Figure this)