Are we how we are due to what we learned from our parents?

I just wrote a little observation in the story group about how I was as a young girl. Does it hold true with each and every adult that we are as we are due to what we learned at a young age? How much of our character really was formed from our very eary years? Would some of this hold true even now, when looking at world events and trying to understand our enormous differences between people of different nations??