How do I tell my son about the birds and the bees?

My oldest son needs to be taught about the Birds and the Bees. I think the first thing I'm going to do is ask him if he remembers how our cat had that huge litter of kittens and passed away. Then I'll tell him that if he ever sees a girl with her pants off, she will become pregnant with 12 babies and die too.

What I need is a good ice breaker so that I can lead into the conversation naturally. Maybe while he's watching Transformers I could say, "Hey, you know what's neat about how the way Autobots are created by Primus? Its so close to real life except that instead of the AllSpark generating life into the robot, a man ejaculates sperm into a womans vaginal canal which fertilizes her egg and creates an embryo."

I think this is going to go over very well.

Suggested Reading: Mommy, Daddy, Where Do Babies Come From? Gift Set