I read the piece in the paper, and it struck me that the programme could end up focussing on family skeletons. We all know that our family trees are distinctly iffy because there's supposedly a 10% chance of any child not being the issue of its putative father (that was the finding of a recent study). If you find, as in Thatcher's case, that the DNA points to someone from distant parts, it could really put the cat among the pigeons.