This type of advert should be blacklisted, if you see an advert that is inappropriate, it is important that you not only get the link, but also screenshot it. If you see adverts like this frequently, it may be a sign that your computer is infected with some form of adware.
Google ads are not only based on the contents in the page but also on the other adsense-enabled sites you visited, unless you manually opted out (I don't remember the link to make so).
There are two possible solutions. 1) Try Opera, blocks ad links 2) Get an ad-blocking extension(Simon will be a tiny bit sadder if you do(as suggests "Please don't block the ads :(" ))