Nearly everything we do affects our DNA. That's what's so clever about it! It seems logical that these changes, or at least some of them, will be passed on with reproduction. Obviously we are born to 'know' lots of things; much of this knowledge has been passed down the generations from before there even were humans.
Just to make things even more interesting, it's now been found that pregnant women receive cells from the foetus (microchimerism.) As well as inheriting from the mother, baby gives something back! Subsequent babies, as well as passing their own cells to the mother, also receive a tiny amount of the cells 'donated' by their older siblings. So there really is a little of each child in the mother, and a little of all the older siblings in each child :)
Amazing stuff, biochemistry, innit?!
So what was your "Aha!", DeckSwabber - what did this explain for you?