The people who come from religious families are probably more up front with their atheism as those who did not grow up with religion did not have to change there identity or beliefs so it means less to them.

My parents were atheists. My mother had to sneak in a manger & barn animals under the tree. My Dad did n't want me exposed to the doctrine. All I wanted was to play with the animals around a baby in a cradle. What's the big deal?

I am from a believing mom who did not practice any religion after I was 6. I hear that is one of her regrets. My dad (who I did not live with) was atheist. I consider that I was raised 100% without religion.