Dear Starshine,

I love a girl. She is my first cousin (my maternal uncle's daughter) and she loves me, too. We are planning to marry after a few years. I am from India, and in India marrying your cousin is very common. But I need to get some things clear. My uncle (let's call him person A) and aunt (person B) are cousins and are married. If I marry my cousin (daughter of A and B), could this have an effect on future generations, as the same genes have been circulated in the family? I started to worry when I saw that my cousin (son of A and B) was always ill. My worry is, what if my children have health problems like him? Would it be wise to break up with her in the early stages, or am I thinking about this wrongly?

I admit the idea skeeves me out a little, but I have no good explanation for such squeamishness. Perhaps if you met my cousins, you'd understand.

Kissin' cousins are stigmatized in the U.S.; it's illegal to marry your cousin in 30 states. But 10 to 20 percent of worldwide marriages are between cousins — and historically, the rate was much higher than that.

There have to be some real advantages to marrying within one's family. Your spouse was probably brought up with values similar to yours, and has spent decades developing a healthy tolerance for your crazy mother. Plus, think how much smaller (read: cheaper) the wedding can be!

The main argument against cousin marriage, of course, is biological. When people from the same gene pool reproduce, their offspring are more likely to inherit recessive traits — including genetic disorders. (Ironically, Charles Darwin was married to his cousin.) But the risks still aren't all that high.

A UK study just last week revealed that parents who are blood relatives are only six percent more likely than the general population to have a child with a birth defect; it's no greater than the risk for mothers over age 34. That percentage might increase when one of the parents is already the child of first cousins — but you could both get genetic testing to find out more.

Meanwhile, consider another downside of marrying within your family: If your marriage fails, you can't divorce the whole brood. Awkward!

It seems that neither Indian traditions nor American taboos can prevent your marriage from being like everyone else's: full of risks and void of guarantees. But any relationship that springs from the words "I love a girl, and she loves me, too" has a better shot than most.

Send me your dilemmas via email: ToughLove@TheWeek.com. And follow me on Twitter: @ToughLoveAdvice.