Just a couple of things about WDYTYA.
Firstly, the programmes aren't made by the BBC, but by a company called 'Wall to Wall' who pay the researchers and arrange the journeys the celebs take.
The BBC just buys the programmes, although the BBC Family History web pages (not the message board) have a lot about WDYTYA and links to topics related to the programmes. It does look as if all our complaints that they make it look too easy have borne fruit because there is now a section entitled 'How we did it' which gives more info on the archives etc in each programme
http://www.bbc.co.uk/whodoyouthinkyouare/new-stories/jerry-springer/how-we-did-it_1.shtml
It actually says his parents never talked about it.
ps JS was born in a Tube station during the Blitz!