DNA can't contain enough information for fully specifying all of the features that fertile women ought to have and hardcode you into being attracted to all of them. It encodes proteins that most of the time result in functioning human brains, with different parts of the brain being in proximity to other parts that most of the time end up causing you to reproduce.

This person is my mom: a woman. Titties feed me. And those get stored in your brain, and then hopefully at some point as you get older your parents teach you about men and women more generally, and then the parts of your brain where tits and women get stored are close enough to the part of your brain that has sexual arousal that they get connected. And all of these are probabilistic and messy connections and it's not inevitable that everything hooks up perfectly every time. It's throwing darts at a dartboard and hoping it hits fertile women in the center. So the brain takes a shotgun approach. Better to be attracted to five times as many things as necessary rather than one fifth, because if you have or want to have sex with five things and one of them is an adult human female and the other four aren't then at least you have a kid.

Your rational intelligent brain knows what a woman is, but doesn't care. Your instincts are stupid and confused and are like "I dunno, women have feet, might as well fuck those. I saw a hot woman wearing green as a kid, might as well fuck some grass. I saw a sexy rabbit cartoon as a kid, might as well be a furry." and maybe somewhere along the line a real woman might be involved and get pregnant. It doesn't always work but sometimes it does.