The ABC's of the Human Body

When I was a young girl my mother ensured I knew all there was to know about the human body, specifically the female body. I could explain in detail menstruation and on in my elementary years. Kids would come to me with their questions. I do not remember the "sex" talk as much as the redundant because of the amount of time I heard "sex bad" talk. Every source of media was scrutinized for its ability to encourage or discourage sex. MTV was brand new in all that time and I felt so abused by missing out on that. I get a lot of that now especially mom being an older teen when she had me. TV is way worse now then it was then. But back to the topic..
The kids have talked before about the human body but mostly in relation to having babies. When I was pregnant with #2 and #3 I watched the show "A Baby Story" a great deal and clearly left an impression on #1. He would say babies come out of the mom's butt and they scream a lot, ha!
Somewhere over time with #2 being very curious about all things female we discussed the difference between a c-section and natural delivery. I never completely said more than the baby comes from a mom's private parts as that is easiest term with both sex children. It is all encompassing. #2 brings up the baby that never was, though there were 3 of those only the one I had surgery for stands out to her. She asks what its name would have been, what sex would it, what would her name be if it was here and on.
Tonight was different because it was #3 who pointedly asked how he came out of me. The kids already know that #1 and #4 were c-section though they think of it as "cut out of my belly". I guess my phrase of naturally left holes for him. In all these years the older two never asked specifically more. I decided now was as good a time as any. He was in his bed alone too. I began to explain the physical differences between male and female but he needed more. I said would you like to see a picture, and he emphatically agreed. The trusty book my mother used for me popped in my head. I retrieved it, showed pics side by side of man/woman (inside anatomy only). Then I showed him a drawing of a baby being born and explained. This conversation was easy and it was factual. He was interested not grossed out and Daddy bailed shortly after seeing what we were doing.
As I said goodnight I took the book with me and went through these same motions with the other two. Oddly enough when I asked #1 where a baby was born he said through the moms butt even though I know I have explained. He also said the difference between a boy and a girl was a girl had a butt and a boy had a butt and "this thing" pointing to his own parts. Umm guess I should make sure he knows what his parts are called! He was interested, clearly fighting being uncomfortable at first but with a factual book in hand he jumped all the way in. He does like to read and learn. I struggled not laughing when I told him the name for scrotum or nicknamed balls. He said, "Oh that's why someone will say I am gonna kick you in the balls."
#2 LOVED the pics of a baby being born and also was unaware of what her own parts or boy parts are called. I guess generalizing private parts kinda back fired. Funny how #3 spurs me to do things with the big 3. They all learned to ride their bikes together, independent showers began within a small time period and now this. Whew, I hope I don't have the bird and the bees talk with all 3 in one night too!!