Not Sure

Recently my husband and I noticed that our ten year old son was becoming curious about sex. I was admittedly a little surprised because I thought he was too young.
I mentioned this to my husband one night when we were in bed. He said that he wasn't surprised and how maybe we should have a talk with him about the subject. He said how it would be better if I did this, and then I could just show him.
I didn't know what to think about the idea of me showing our son and having sex with him. My husband sees nothing wrong with this.
Do other mothers do this?