Birth control for women does have hormonal implications for women.

When a woman is ovulating, she gets tingles from genetic markers, muscles, dominance and the like.

On birth control the lizard brain is providing less input, tingles are much weaker and so she chooses with her eyes, picking the most aesthetic choice instead of picking with her vagina.

It's like asking a guy who the prettiest girl is after he just finished jacking off for the tenth time that day and he has no sexual interest left. he'll pick the one with the prettiest classical face and no curves, instead of the cute 5'2 chick with great tits and ass that'd normally get him going.

Don't mistake preference for Vagina soaking.