I have seen, first hand, that nature has a strong pull in determining these traits.
I am no psychologist, not a doctor, or a professor, I am a Mom. More specifically, I am Katelyne and Tyler's Mom.
Katelyne is a girly girl in every sense of the word. She is amazing. She loves purple and pink, thinks Tiaras complete any outfit, tutu's can be worn everywhere, dirt on you is just unacceptable and eyeshadow is a must to leave the house. If she falls, you are immediately teleported to a twilight of drama - tears, screams, band aids and lots of hugs...
And, Tyler. Tyler was born with brawn and gusto. Equally, Tyler is amazing. Even before he could walk, he had one speed: GO. He will climb anything, scale the dog, throws everything, push everything and if he falls, he may whimper, but 99.9% of the time, he will literally shake his head and continue on.
As I awake every morning I stumble into the kitchen and make my coffee, on my way back down the hall, usually I am greeted by my little Princess who requires immediate hugs, and kisses and snuggles - I whole-hearted oblige. About 20 minutes later, I change out my tiara and replace it with my hard hat as Tyler wakes... he requires an immediate trip to the kitchen for food and milk. I find myself constantly interchanging my tiara/hard hat daily.... naturally, my children are two completely different beings and that is the amazing part of them both.
I am a proud Mom... I have the best of both worlds and a pretty awesome Hubby to go along with the package. Each day is different from the last, and I honestly could not operate any other way.