Before my youngest turned two he had been sailing in the Apostle Islands, BVI, Duluth and San Diego bay. He has "sailed" our twenty two footer, had a few excursions on a Catalina 36 and spent a week on a Beneteau 323.
He wears a lifejacket and tether any time he is out of the cabin. When any or all of our three children are on board we always wear lifejackets and we always take it easy. We are always the first ones with the second reef and storm jib.
My first wife was involved in a caspize/sinking as a kid and it put a serious crimp in my hobby... my second wife loves sailing and I want to keep it that way!