Doctors are emphatically not con artists.
I applaud you wife's reasoned decision, clearly she is in control of her own destiny and her decision (if by unfortunate chance it is the wrong one) will mostly affect her and her immediate family.
But if we spend a good sized fortune and several years educating someone I really wonder why we'd bother with that if all that it would take to counteract all that effort and knowledge would be a lay persons reading of the medical literature. Most of which is not exactly written for easy consumption by the general public.
Whether you're in a risk group for certain cancers depends on a lot of factors and you'd need to know all of those to make a weighted decision. This is not always as easy as applying the general case to yourself calling it a day.
Age and sex are obviously the big ones but there are many (not sure how many) contributing factors that may cause doctors to be more concerned about one individual than another. We call those people specialists because we recognize that the amount of knowledge required is typically larger than what one person can acquire in a lifetime.
The time when I'm going to trust my own interpretation of a pile of google'd medical papers over a qualified specialist is still a while away.
In the meantime I'm terribly happy I'm not a medical doctor, I'd hate to have to continuously defend each and every minor decision to a general public that I'd be trying to help in an already time-constrained practice. It's hard enough when non-technical (read: totally clueless) customers question evaluations of technical issues based on some popular text they've been reading, at least there are usually no lives on the line.