What age do you think parents of opposite sex children should stop

as long as they use a condom, i see no real issue with it.

Depends. My brother's stupid so get them in their own bed EARLY, or else they'll grow up fucked as hell. Trust me.

0.
You could squish your child.

I don't think that I ever slept in my parent's bed for more than just occasional "bad dream" nights.

My brother had a problem with this. He slept in his own bed (Finally!) when he was eight. I stopped when I was five.

when junior starts having wet dreams... to be continued after the age of 18 ... >:-)