Google AdSense ads are based on the viewer's browsing history, though I agree they don't always make sense. Mostly I see ones that are relevant to me but some of them I don't know how Google thinks I'd be interested.
It is possible to block ads by category and by specific website. I don't know who takes care of the AdSense account for WikiTree (presumably Chris or one of the behind-the-scenes guys), but it's possible they may be able to do that. Blocking ads lowers the profitability of the ad space, though, so it's not something to be done excessively on a site that's maintained by ads.