If you had read some psychological works from _this_ century, i'm sure you would agree with me

The first definition for "instinct" i just googled up says this:
"An inborn pattern of behavior that is characteristic of a species and is often a response to specific environmental stimuli"
I see two problems with this definition, when i try to apply it to human behavioral patterns.
First, it can't be inborn. If you'd take a newborn girl and let her grow up without any social contacts (sounds like a great idea, right? people did stuff like that already) the result's wouldn't be pretty. Despite her having no idea how to interact with other people, how would she know that she's got to bang some dude to get food and shelter? She wouldn't.
The next problem comes with "characteristic of a species", because it implies that this particular behavior holds true to every single female human in existence. I'm sure you realize that there are women on this planet that don't roll that way.
Your body can't dictate your actions.
It CAN have an influence, though. For example, some people are more likely to get addicted to drugs than others-
but that's not because their DNA has "JUNKIE" written all over it, it's because different brains tend to respond with different levels of neurotransmitters to certain stimuli.
Oh and i never said there's no difference between men and women, thank you
