Reykjavík, the most densely populated city in Iceland, only has about 120,000 inhabitants, and is famous for harboring a pretty sweet bar scene. Now, unlike the rest of Europe, Reykjavík isn't exactly bursting with big nightclubs pulsing with revelers. Rather, the town that birthed Björk is better known for its crammed, kitschy watering holes, which hip party-goers only head for after 12 or 1 a.m.

But with a tiny population — Iceland itself only has about 320,000 people, or about half of Washington, D.C. — the hookup scene can get a bit… well, tricky. While Iceland is known for embracing its latent weirdness, drunkenly embracing a maybe-cousin is still an obvious no-no.

That's why a new Android app is quickly becoming the next best thing since the country's beer ban was lifted in 1989. The Islendingabok, or Iceland Book, is a genealogical database that keeps tabs on all the island's inhabitants — sometimes as far back as the 9th century. The database's new app, IslendingaApp (you guessed it! Iceland App), has one nifty feature that's drawing some attention: An early warning system that tells you if the sexy stranger you're undressing with your eyes is, in fact, one of your relatives.

Consider it an "incest-prevention alarm," Arnar Freyr Adalsteinsson, one of IslendingaApp's developers, tells Bloomberg Businessweek. To activate its righteous wing-manning powers, all you two have to do is press your phones together. "When you bump, it shows your nearest common ancestors. If you bump with someone who's too closely related, you get an alarm sound and a text warning."

It should be noted that IslendingaApp does other stuff, too: It has a birthday calendar for all your relatives, for example. But its ability to protect the island nation's gene pool is what's understandably evoking the most curiosity; its creators, in fact, are promoting the service with a clever little motto: "Bump in the app before you bump in the bed."