Every few weeks, someone shows up in the AdSense Help forums asking if their site is "too adult" for AdSense, and usually claiming that the rules are confusing, ambiguous, or poorly defined.

The reality, though, is that there's really nothing ambiguous about it.  All it takes is a little common sense.

Educational contexts are excepted, to a certain degree.  Fine art contexts are excepted, to a certain degree.  When I was in middle school they managed to show us images of sexual activity without crossing that line - line drawing or graphic art diagrams, neutral presentation of factual information without any appeal to prurient interest.  Even in the throes of adolescence when a stiff wind was enough to spark the reproductive impulses of entire battalions of teenagers, it was pretty difficult to suggest that any of that content would appeal to our baser natures.

Fine art is a little tougher to gauge, but still not all that ambivalent.  A critical review of Michaelangelo's "David" would almost certainly pass inspection.  A critical review of Robert Mappelthorpe's notorious self-portrait showing him with a leather whip inserted into a rather delicate area of the human body that is not generally understood to be a storage container for leather implements wouldn't, if the photo was reproduced as part of the review anyway.

Ask yourself:  What would the general public reaction be if an eighth-grade teacher displayed this material to her students as classwork?  Disregard the extremists on both ends - even if you are one - and use a little common sense.  Leave aside the intentional argumentative hairsplitting and just think.  A graphic (in the sense of 'not photographic') image showing tab A in slot B with handy little labels and an accompanying article dryly explaining the mechanics of human reproduction is quite different from a picture of this month's "Hustler" centerfold or a screen cap from whatever's hot in video porn these days.  A discussion of Rodin's "The Kiss" is quite a different proposition than an in-situ demonstration photo of Adam & Eve's "The Rabbit." 

I would (and have) viewed Rodin's work with my teenage daughter.  I don't think we'd be browsing the Adam & Eve marital aid website together.  A photoreproduction of Goya's La maja desnuda would almost certainly pass muster.  A photoreproduction of Miss September from "Big'uns" magazine wouldn't, even putting aside the copyright issues.

Exposed breasts on the statue of Justice that used to sit behind the head of the Attorney General during press conferences until noted fundamentalist John Ashcroft ordered it covered?  Almost certainly will pass.  Exposed breasts on Traci Lords from one of her now-illegal films, or the back cover of Girls Gone Wild Volume 932841: The Girls Of Bob's Big Boy at 49th and Maple Street, Swing Shift certainly wouldn't.

It really isn't that hard to figure out, and generally questions of this nature fall in to one of two categories relative to AdSense.  Either someone wants to argue about 'freedom of speech,' which has absolutely zero relevance in this context, or someone wants to figure out how they can walk riiiiiight up to that line without crossing it, so they can draw the porn traffic without sacrificing their AdSense income to do it, which is just dumb, frankly.  It's also worth pointing out that there's generally no need to even worry about 'interpretations' and 'I know it when I see it,' because the person who is planning this little venture is 99.999999% certain to not be producing their own work, and therefore the copyright violation issue would get them even if the adult content didn't...and frankly if they're producing their own porn and still need AdSense to make money, there's a bigger problem (or perhaps a smaller one, he said with a wry grin) involved anyway.

All kidding and extreme examples aside, I think the litmus test I've proposed above is a good one:  What would be the reaction of the average parent - not a hyperconservative religious zealot parent who thinks genitals are bestowed by the Gonad Fairy on the eve of one's 18th birthday, and not a ridiculously liberal or apathetic parent who doesn't care at all or who encourages their kids to surf 'net porn (if such parents exist), but an average parent, a reasonably intelligent and even-headed individual with no particular hangups either in favor of or against sex and sexuality - if their twelve year old's teacher asked them to review this material as a class assignment?

If they would object, or consider objecting, then it's safe to assume that this is Not AdSense Material.

Hope this helps