"You don't understand.  It is biology.  It's a biological clock.  Women are hardwired in our nature to want children.  At some point, the pull is primal and undeniable.  It's in the basic instinct."

"You don't understand.  It's biology.  Black people don't act like us.  They don't have the same basic physical structure.  Their brains aren't as developed and they have…I don't know…different bones that make them better at sports and stuff."

"You don't understand.  He's a little fag.  It's biology.  He was born kind of less of a man.  He has all that asthma and he's weak like a girl.  He was born weak and that's what he has to learn to live with."

In 1869, Francis Galton threw up a theory that intelligence was bred rather than taught.  That it would be "quite practicable to produce a high gifted race of men by judicious marriages during several consecutive generations."  The idea being that who we are and what we do is primarily due to the pre-determined set of factors we are born with.  Today we call this theory eugenics and it has been the basis of theorizing that people cannot exercise free will, that if you are born with a specific set of DNA, that's the best you'll ever do.  Adolf Hitler LOVED this theory.  I think he had a wall tapestry with it in his bedroom.

Funny about Hitler, though.  He was born a little, weak dude.  Kind of sickly.  Brown hair.  And his ideal was the tall, strong, blue-eyed, blonde haired übermensch.  So he worked at it.  He was nurtured to hate Jews, not out of biology, but because he loved Wagner (who hated Jews).  Kid Hitler didn't have a lot of lung capacity.  He nurtured his voice to be able to scream gibberish (contrary to historical record, he wasn't really screaming in German but he was so scary and deranged, the crowds cheered anyway…).  In fact, in spite of his adherence to a genocidal policy of eugenics, Hitler was a poster child for the concept of nurture.

Contrasting Galton's entire body of work isn't that hard.  Nature is that thing that people with grit and determination OVERCOME with proper nurturing.  Look at a little white child playing with a little black child.  Those two kids could give two shits about the skin color difference.  It takes some hardcore nurturing to create hatred based on skin color.  One of those kids is gay but those two kids don't care.  It takes the loving hand of a bigot to craft and nurture the kind of nastiness that pits one kid against the other because of his or her natural sex drive.  The very idea of nurturing sounds all motherly and it is until you think about all the shitty people in the world who nurture the hateful side of humanity.  Then nurture becomes a horrifying system of growing fuckheads.

Yup.  Nature is powerful but it takes some real good nurturing to create a Donald Trump or a Pol Pot.  You know those obnoxious asshats who protest the funerals of dead soldiers because they hate the personal choices these now deceased American patriots had?  That unreasoning fear and hatred was nurtured and grown and cared for.  Watered by the milk of human disdain and photosynthesized by the glower of ugly intolerance.  It didn't happen because these dumbasses were born stupid or with hair on their palms.  It was built one hate brick at a time.

"I do understand.  Biology made him weak but he overcame that asthma and smallness of stature and became Theodore Roosevelt."

"I do understand.  Biology made you someone who sees people not skin color.  Your fucking parents and an institutionally racist system combined with a constant stream of media that indoctrinates you with images of black people as less turned you into an intolerant bigot."

"Oh.  I understand the biology behind wanting kids.  Guys have a biological imperative, too.  Ours is to fuck and impregnate every woman we see.  We can't help it - it's biology.  We are hardwired to want to spread our seed in as many directions and in as many vaginas as we can possibly stick our things into.  But, in an advanced, modern society with a proclivity toward religiously mandated monogamy and the refusal to treat woman as nothing more than baby factories, our reliance on something as silly as our nature to justify this as necessary is kind of stupid."