Do you see what I see?

The other day we were coloring, and I know that experts say you can't tell until a child is around 3 years old, but I couldn't help but notice the difference between this.....

and this.....

Coincidence? I'm not so sure. 

I am a lefty with two right-handed parents and two right-handed siblings. J is right-handed as are both of his parents and all 3 of his siblings. Interestingly, J and two of his three siblings have paired with left-handed people. My brother also married a lefty. My best friend is right-handed although both of her parents are lefties! While I know it is determined before birth, I am not certain exactly how handedness is determined in our inner workings. Any genetics/bio people out there have an explanation? It doesn't seem to be as simple as a Punnett square which represents the extent of my genetics knowledge. 

As for C, she definitely uses both hands when coloring or feeding herself. And she doesn't always hold a crayon perfectly in her left hand. She rarely holds it "like a pencil" in her right hand though, and I would say she seems to prefer using her left hand maybe 70% of the time. I would be tickled (and I know a few of her aunts and uncles would be, too) if she turned out to be a lefty, but I'm very aware that it's not something you can influence and that trying to do so can really cause a kid difficulty. I'm just an observer when it comes to crayons and sometimes I have to take pictures to prove to myself that I'm not just making up what I want to see :)  

Anyone else notice a dominant hand in their child before 3 years old? Anyone have some insight into how our hand-dominance is determined? Do share! :D