Hee hee hee... Even in a place as freeminded as this no-one wants to think of their parents "at it". My other half has a six year old son and whilst he doesn't object to seeing us being "loved up" with each other in front of him, he pleads with us not to kiss each other if his friends come over. Oh dear... he's going to have some embarassing times while he's growing up

As for the genetics question, it's going to be a combination of nature (genetics) and nurture (the environment) and there's never a definitive answer in that old debate.