Nature or Nurture?

My niece, Elizabeth, is visiting (with my sister Allison). And, if y'all know Allison she is even lower maintenance (and more tom-boyish) than I am. But Elizabeth is the ultimate girly-girl. She doesn't like to be dirty. She loves jewelry and strappy shoes. She wants her fingernalis & toenails painted all the time. She won't go near bugs. She hates movies with monsters and beasts, but loves movies with princesses and singing. She dances and prances around on her tiptoes.
Ethan & Nolan on the other hand are 100% stereotypical boys (With the exception of Nolan crawling into any shoes that he can find, and most often they are mine - We call him "our little hermit crab"). They love to play in the dirt & mud. A selling point is telling them there are cars or diinosaurs or monsters in the movie/book. But they are disinterested in anything that involves princesses. They do love to dance - but their dancing is jumping, shaking & kicking movements. They love to wrestle.
I just wonder - Were they born that way? Or did we raise them to be?