Our talks started several years ago, when my oldest was around 3 (and I've had similar talks with my youngest, who's about to be 5). She happened in the bathroom, and noticed blood in my panties. When she started to freak out, thinking I was hurt, I explained that it was "special blood," that stays inside Mommy's tummy (I later explained the exact location is called the uterus), and it helps to grow a baby, when it's just a teeny tiny egg. Further talks explained that each month, if there's no baby in Mommy's tummy, I don't need the blood any more, so it comes out, and my body makes more, for next month.
My oldest noticed that she had -three- holes, -down there.- I simply explained, that one is where tee-tee comes out, one is for poo-poo, and the middle one (called the vagina), is where the special blood and babies come out.
Later, when they asked how the baby got in there, I explained that mommies have eggs inside their bodies, and the daddy plants a seed, to make it grow into a baby. When my youngest learned this, not long ago, she GASPED, then exclaimed with fascination, "-I- was a baby PLANT?!" LOL!!!
"No, it was a -BABY- seed." She seemed perfectly satisfied with that explanation.
We haven't yet gotten into the mechanics of it all, and I'm teaching the proper names for things, as they grow and learn more. I'm hoping it will be an easy transition, since they aren't -totally- in the dark about everything.
Oh, and about condoning sex under mom and dad's roof: ABSOLUTELY NOT. And if I even have a suspicion that they're having sex elsewhere, we'll be putting a stop to that elsewhere.
My mom told me as a teenager, "your father and I were virgins when we got married, but we did everything -but-. . ." Yes, it was kinda gross to hear that about your parents, but in her defense, she was trying to discourage premarital -intercourse-. . . I keep telling myself, that I have the advantage of being able to tell my kids, "I wasted my virginity, before I got married, and it was SO not worth it!"
Best wishes!
M.