The "talk" for a seven year old

Seven year old, Bob, has asked where babies come from several times over the past few weeks.  He has asked at odd times, like at the dinner table or in the car with all of his brothers around, so I have avoided answering him by saying we could talk about it later, when it is just the two of us.

Two nights ago, though, he asked again while I was helping him to get ready for bed and I could no longer put off the inevitable.  My mind raced for the right answer. 

Each child is unique and each is ready for a different level of information and detail and different times.  Bob is bright and knows a lot, but his "awareness" of human relations is not high.

So, here's what I said.  "There's a special kind of seed in a mommy and a special kind of seed in a daddy.  When the mommy and daddy want to make a baby, they give each other a special kind of hug and the seeds go together in the mommy and grow into a baby."

He gave a satisfying, "Oh.  Thanks, Mom," smiled and dashed out the door to brush his teeth.  No further questions!

Phew.

I recently purchased two books about puberty and S-E-X for my preteen and teenaged boys.  I pre-read the books and found that the one that is all about puberty: American Medical Association Boy's Guide to Becoming a Teen  is age appropriate for 10 year old Dwight, but It's Perfectly Normal: Changing Bodies, Growing Up, Sex, and Sexual Health (The Family Library)   is too advanced, in other words, TMI, for Dwight, but will be a good resource for 13 year old Zack. 

This is a tricky topic for many parents but it cannot be ignored.  Ignorance leads to no good.  So I hope my experience will help other parents.