What they should teach in genetics class

The curse of the geneticist is being out to dinner or whatever and seeing a family with a young child and instantly being able to tell that the child is not related to the man. Brown eyed kid, with blue eyed parents, etc. It seems like something you should mention, hey buddy you should talk to your wife about... But it really isn't your business. The Punnett square is like the Force, it is has a light and a dark side, and those who understanding wield a great but terrible power… ;)