Birds and The Bees - Already?

Today we got a note from the teacher. Apparently our son was speaking in appropriately on the play ground. He asked one of his best girl friends if she liked his wiener. Hmmm, we thought that was odd. He said he was just joking and that she laughed. He didn't understand why this was a problem. He began to cry a lot! He was so confused. My dh thought it was time to have the birds and the bees talk to help him understand the inappropriateness of it all. Oh dear! I sat here and just listen to them talk about all the private body parts of men and women. Geez! He's only 7. He was very into the conversation just because he's so clinical about it all and wants to know the terms, etc. He stopped crying though and we think he's got a better understanding now.