My father's left handed, I'm left handed, my sister's ambidextrous. A couple of her kids are left handed. There is certainly a genetic component.

My son's too young yet to have a dominant hand, but I make a point of putting things in his left hand. It's a lifestyle choice.

I grew up in Australia in the 70s and 80s, and I don't recall any prejudice against left-handers at the time. I never even really thought about the difficulties of using right-handed implements. It's just the way things were.

My father does tell a story, from the early 50s, where his mother had to forcibly intervene at his primary school, where they were trying to force him to use his left hand.