Just ask him why he thinks sex is dirty! He may just think girl have kutees or something and that’s what he means. Let his response decide your response, rather than assuming he’s ready for “the talk” - which he may be no where near ready for.
We just answer questions as they come up in a simple and basic manner and stop there until the next question comes up. My 8 year old knows girls are different physically, it takes a husband and wife to make a baby. When I was pregnant last time he wanted to know how the baby got there, and we said "God sent us the baby.) and he was happy with that. We bought 2 books: * Angels in the Waters and Before You Were Born.*
Now, my 10 year old is wanting to know exactly how God did that, so we’ve gone into a little more detail there. Daddys have sperm that travels to the mommys egg. God brings the egg and the sperm together to make a new soul. The soul’s body starts to grow inside the mommy for about 9 months before it’s ready to join the world ourside the tummy. Then mommy has to push the baby out of her “privates” or sometimes that doesn’t work so the drs. have to cut the baby our of her stomach instead, so that the baby can be born into the world. Yes, it hurts quite a bit, but it’s worth it to both the mommy and the daddy.
So far, that’s been enough detail for him. Though I’m sure he’ll have many more questions the next time I get pregnant. I just don’t see any purpose to giving more information than neccessary at a time. It’s not something they should be going out and practicing yet and I’ve never heard of any adult who wasn’t able to “figure things out” without a graphic picture. Our grandparents and great-grandparents certainly caught on quick enough. They need to know about personal boundaries, that others are not ever allowed to tough them in certain ways at all, for safety reasons and that’s enough for quite some time when they are young.
Good luck!