that's silly. has she had cancer 4 times? my grandfather's mother and aunts lived until their late 90s. that didn't stop him from dying of cancer when he was 76.
it's a legitimate concern. and given McCain's various senior moments on the campaign trail this year -- something, to their credit, the Obama campaign has not pounced on -- we have reason to be concerned we'll get Reagan's second term during McCain's first.
While there are always exceptions to everything, genetic factors are considered very important in living to 100 or beyond. Its not irrelevent or silly. Reagan would have easily of won a third term.