Nature v. nuture

I love kids.  Alright, I said it.  It's out there on the interwebs for all to see and know.  They're such fascinating little specimens, what we would all be like had the world not gotten in the way.  But on occasion, I wonder for how much genetics can really account.

Perhaps this preoccupation begins with my mother, who is a twin.  As might be expected, she and her twin have a heightened sense of sibling rivalry when it comes to each other, which has continued to flourish into their 60's.

Here is one of my favorite pictures of the two from their youth - and also the start of my questions.  You have two children who are born into an identical environment, raised by the same family, arguably loved the same amount - so why does my mother (on the left) lack the apparent happiness of my aunt (on the right)?  What's really fascinating is that they are still differentiable by these smiles, which they continue to produce upon photographic opportunities.

At what point along the way does our environment take over in the creation of our personalities, if it does so at all?  Well, okay, yes it does contribute.  That's the beauty of twins, especially identical ones - all the same genetic material, but a different overall outcome somehow.  While it would seem natural to assume equal treatment, the amount of variables contributing to each experience each day is vastly staggering.

This was truly brought to mind last night while babysitting two darling little boys.  The younger one has the most adorable blue eyes and at some point along the way, he seemed to have figured this out.  I've often conversed with his mother about whether the boys get different treatment because of their mannerisms.  But is it because their genes directly influence their behavior or because the responses to their genes do?  The younger one is cute and knows it, so he uses this to his advantage - is this a cute-linked behavior gene or just because it's a trait to which we are all drawn?  ("Who's a cute little boy?" "Aren't you such a smart little girl?")  Do these comments of encouragement we feed to children ultimately determine the personalities they will develop?

Okay, well, I'm curious about this so I'll research and report back to you all throughout this week.  Stay tuned!  =)