It sounded like fun. It always does until someone gets hurt.

For $100 apiece, Sue and I got our DNA tested. It's simple: You sign up online, they send you a little kit, you spit into a fancy test tube and send it back. Six weeks later, voila -- you know for sure where your ancestors came from. None of this "I was King Henry the Eighth in a past life" nonsense, but how much of me is European, how much is Asian, how much is African? Am I a carrier of some genetic disease? How many of my relatives have taken this test?

The first thing most people say when they find out we did this is, "Why? What about your privacy?" Sorry, but if you have a Facebook page, a credit card or a driver's license, your privacy ship has already sailed. And really, what does it matter if someone knows my ethnic heritage or who my fifth and sixth cousins are? I don't even care that much; why would anyone else?

The second question people ask is, "What did you find out? Were there any surprises?"

Oh, yeah, there was a surprise. The legend in my family, from the way my grandparents look in old, fading photographs, is that we have some Native American ancestry. But unless the Native Americans came over here from Ireland originally, the answer is a big honking "no." If I was anything in a past life, it was one of the Clancy Brothers.

No, the big surprise is that I am 2.6 percent Neanderthal. No wonder Mensa never called me back. First, I didn't know Neanderthals and humans could mate. How can I have any of their genes? Sue had a lot of fun with that -- until she opened her file. Turns out she's 2.5 percent Neanderthal. The rest of her is more Irish than "Riverdance." Still, she's less caveman than I am, which she now mentions with depressing regularity. In public. Some things, it turns out, should be kept private.

The results also told me that I probably have brown hair and brown eyes, and on and on, then listed genetic markers I carry for diseases and syndromes which, at my age, I already have: arthritis, atrial fibrillation, male pattern baldness, etc. Having a marker for a disease or a cancer doesn't mean you will get it, because most diseases need an environmental trigger, too. It seems I pulled a lot of triggers. But what if I had been tested as a child? Would I have lived the same kind of life?

The test tells you which of your relatives, known and unknown, have also taken this test. Since the test is only available to people who have an extra $100 handy, most of our distant relatives are not going to be in this database. Mine lists about 260 people I'm related to, most of them fifth or sixth cousins who live all over the world. You can choose to have your identity open to these people, or not. I chose "not." It's bad enough that Sue knows I'm Neanderthal; I don't need distant cousins I never met lording it over me.

But the most interesting of all is that, if you like, you can become part of the quest to break all the DNA codes. By answering questions about your health history and your environment, anonymously if you like, it helps find new markers. And there are some real oddball questions: "Do you like the taste of cilantro?" It turns out that about 17 percent of people of European descent hate it. It sounds silly, but what if they find that every cilantro-phobe also has the marker for something else, something serious and hard to detect? Suddenly we may discover a simple, inexpensive test for some condition.

Or maybe we'll find out Neanderthals are much smarter than we thought.

Contact Jim Mullen at JimMullenBooks.com.