When I was a child I didn't even think of it because I really didn't know anything about sex. When I was a teen I learned some things from the other kids. In fact, I think it was in the 70s they started sex-ed??
Anyway, looking back, I don't think of it as being revolting to think of my mom with my dad. I think it must have been sad in some ways because my mom was very uneducated, just the Catholic take on things anyway. Plus, back in that day and before, I'm not so sure women were even "included" except for actually having the baby.