Seems like there’s an app for everything these days—boiling an egg, hailing a cab, cursing in foreign languages—but avoiding sleeping with your cousin?

Well, yes, there’s an app for that too. In Iceland.

The new “incest prevention” app is a debatably handy new byproduct of a large online genealogical database about the inhabitants of Iceland called Íslendingabók (translated as The Book of Icelanders). The app allows users to bump their phones together and instantly find out whether or not they are related.

“Bump in the app before you bump in bed,” is the totally awesome tag line for the new product, created by a group of Software Engineering students at the University of Iceland named Sad Engineer Studios.

Sleeping with a relative is more of an issue in Iceland than most other territories due to the country’s small size—Iceland has just 320,000 residents, compared with more than 300 million people in the U.S.—as well as the lack of immigration and the peculiar way that surnames are constructed in the country.

Your surname is not passed down through the generations as it is in most Western cultures. Instead, your surname is your mother or father’s first name, with the word “son” or “dottir” suffixed.

So, to use Iceland’s most famous export as an example, all that the surname of Björk Guðmundsdóttir tells us about her heritage is that her mother’s first name was Guðmund. Information which, if exchanged in a bar late at night when Sigur Ros is playing really loudly, may not give many hints as to exact lineage or potential problems at the next family get-together. People are listed in the phone book by their first names in Iceland.

One of the developers of the new app, Arnar Freyr Aðalsteinsson, explained: “Icelandic names differ from most current Western name systems as our surname reflects the immediate father (or in some cases mother) of the child and not the historic family lineage. For example, my last name indicates that I’m the son of Aðalsteinn (my father’s name) so therefore I am Aðalsteinsson.”

“The idea for the incest-prevention feature comes from our culture,” he said. “Accidentally sleeping with a relative has been a running joke in Icelandic culture for a while.”

Arnar said he got involved with the project when the Book of Icelanders ran a contest to create a mobile experience using the database. “We wanted to find new creative uses for the information contained in the database. Our main goal with the app was to implement all existing features of Íslendingabók and also to add some new and exciting features.”

Yes, “exciting” sort of covers it.

“The big feature we introduced was the Bump,” said Arnar. “This feature enables users to find out how two people are related by bumping two phones together and instantly seeing how those two are related. A small, but much talked about feature is the loosely translated ‘Incest Prevention Alarm’ that users can enable through the options menu, which notifies the user if the person he’s bumping with is too closely related.”

The app is proving popular. So far, 4,000 people have downloaded the app from the Google Play Store.

However, Arnar is keen to point out that these are not all likely to be people seeking to prevent kissing their cousins.

“In addition to the already available search function where you can search for and find out how you are related to any other Icelander, we added a birthday calendar to make sure you don’t forget your relative’s birthday. The app even reminds you on the date to guarantee you won’t forget it.”

Only problem is, it might be telling you your girlfriend’s birthday too.