By Amy Feldman

By Amy E. Feldman

PHILADELPHIA (CBS) – What does the law say about marrying a relative?

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A mobile app was just unveiled in Iceland that allows the country’s 320,000 residents to “bump’’ smartphones together to learn if the smart phone owners are relatives, and if so, whether they are too closely related to have another type of relation. The app’s slogan is “bump the app before you bump in bed.’’ Ew.

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While always repulsive, when is it illegal to marry a relative here in the US? That depends on state laws.

It is illegal in all states to marry your mother, father, grandparent, aunt, uncle, niece, nephew, or sibling. As for cousins, most – but not all – states forbid marriage between first cousins. Nope, the states that don’t forbid it are not all in the South.

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Surprised, Massachusetts and Connecticut – neither of which ban marriage between first cousins? More surprisingly, there are no laws that forbid marriage between second cousins. Even so, if the fear of genetic diseases doesn’t stop you from dating your second cousin, think about how you’d feel to see the girl with whom you hooked up last weekend at the family reunion this weekend.