Accidental incest may not be a concern for much of the world, but for the mere 320,000 currently living in Iceland, it's a real risk.
"Everyone has heard the story of going to a family event and running into a girl you hooked up with some time ago," Icelander Einar Mangusson told the Associated Press. "It's not a good feeling when you realize that girl is a second cousin."
Which is why Magnusson has a new app on his smartphone to protect him against just that.
Called Islendiga-App, meaning "App of Icelanders," two people need only tap their phones to see if their apples fall too close on the family tree.
Created by three University of Iceland software engineering students, the app was the response to a challenge for "new creative uses" of the Islendingabok, "Book of Icelanders," which features a database of residents and their family trees stretching back 1,200 years - a feat made possible by the fact that nearly everyone descends from the same group of 9th-century Viking settlers.
"The Icelandic sagas, written about 1,000 years ago, all begin with page after page of genealogy," Kari Stefansson of the Icelandic biotech company deCODE Genetics told the AP. "It was the common man documenting his own history."
Though the original plan was merely to show people common ancestry, developer Arnar Freyr Adalsteinsson said the incest alarm has made the most news.
Though, he fears that as it does, it may be spreading the wrong message about Iceland.
"The Icelandic nation is not inbred," he said.
And, ultimately, the app only alerts people if they have a common grandfather - and most people already are aware of their first cousins.
Still, this hasn't stopped the team from assigning the program the slogan, "Bump the app before you bump in bed."