"When I grow up I'm going to marry my sister."
"Oh unfortunately you can't do that, how about one of her friends?"
"No I love my sister. Why can't I marry her?"
"It is against the law."
"OK then I will marry my brother."
"That too is against the law."
" Can I marry one of his friends?"
" I guess you could if you wanted too."
"No I think I'll marry Mittens (the cat.)"
More wine please!