Bennett Greenspan had hit a dead end. Years of researching his family tree through records and documents revealed roots in Argentina, but he ran out of leads looking for his maternal great-grandfather.



The heart of Family Tree DNA's business is its "surname projects," which consist of databases of DNA samples from people with the same last names. In five years, the company has developed databases of roughly 6,000 surnames.

Genealogists can check to see if their surnames are listed on the company's Web site, If so, they can purchase DNA test kits, mail back the required cheek scrapings, and wait to see if their genetic makeup matches that of any of the others already in the database. Outside the databases, any two people can be tested to see if they're related.

The company offers 13 tests or test packages, which range from $100 to $419. The most popular are the Y-chromosome tests that trace paternal lineage. A less specific mitochondrial DNA test traces maternal lineage.

Health care reporter Anne Belli discussed the business with Greenspan.

Q: When most people hear about DNA tests, they think about forensic testing on TV shows like CSI, but not genealogy. Do you use the same same kind of test?

A: No. There is no medical benefit to this. We don't do any medical testing, and this is not a paternity test. We are also not running tests like the FBI, which is interested in trying to determine a match to a single person. What we are dealing with is the mundane genealogical hobbyist side. I can tell someone if he is related to four other people with the same last name.

Q: Genealogy was already one of the nation's most popular hobbies. What has DNA testing done for it?

A: At minimum it is just another tool in the arsenal of the well-prepared genealogist. Because its implications are so broad, it has allowed people whose names are almost untraceable, like Smith or Walker, to parse through with the stroke of a brush. What genetics has done in genealogy is create a paradigm shift. In the past, when you hit a paper trail roadblock, you were done. Now you can assemble unrelated lines of people and determine who in those lines are

Q: So how is business?

A: Growing and growing. Revenues have been doubling every year. We initially were shipping just one or two kits a day. Now we are shipping 40 or 50. We shipped 13,000 kits in 2004 and 8,500 in 2003.

Q: What are the two or three most interesting matches made through your customers?

A: The truth is, there are hundreds of interesting connections, like the priest in South Texas who found that the people he matched most closely with were Eastern European Jews. Sometimes we find out about false stories of adoption or paternity. That is just a fact of life, and sometimes it's difficult for people to hear about.

Q: Is it true that if I find someone else with my last name that we're probably related?

A: It is less often true than we think it is. Because history and time blur connections, there needs to be some clear, objective bona fide way to be able to say that two men named Detwiler are truly related to each other, and DNA testing does that.