If they don't ask, when do you tell them?

[PrettyCandles]

Nearly-8yo ds1 knows where babies grow, and how they come out, but has never asked how they got in there in the first place.

Do I wait until he asks (my usual strategy), or do I bring the subject up myself?

By what age should a boy know this sort of thing?

[Dottydot]

6.6 year old ds1 knows that Daddy has seeds and that they come out of his penis. He knows the seeds join with an egg in Mummy and make a baby and he knows where the baby comes out.

What he's got no interest in knowing is exactly how the seeds meet the egg! And I'm waiting until he asks...