Such tests used to cost thousands of dollars apiece. Now they're relatively cheap — and some entrepreneurs see both scientific and commercial potential. This month, the National Geographic Society announced it was teaming up with International Business Machines Corp. and Family Tree DNA of Houston to build a database of 100,000 samples from ethnic groups around the world. National Geographic is selling a service — for $99.95 plus shipping and handling — in which people can send in their own DNA and find out where they fit on humanity's family tree. For example, it might show that a person's ancestors on the male line came out of Africa, through Central Asia and into a particular part of Europe.

Family Tree DNA and several other U.S. companies already offer more narrowly focused services designed to help amateur genealogists solve family riddles. African Ancestry Inc. of Washington, D.C., uses DNA to help individual black Americans figure out what part of Africa their ancestors came from. Trace Genetics Inc. of Richmond, Calif., provides a similar service for Native Americans, among others.

To this race, Sorenson brings nearly 60 years of experience as one of America's most prolific entrepreneurs. The son of a Mormon livestock-yard operator, he was born in 1921 and grew up in a tar-paper shack in Yuba City, Calif. He hoped to become a doctor, but instead spent part of World War II as a missionary for The Church of Jesus Christ of Latter-day Saints in Maine. After 11 years at Upjohn pitching drugs to doctors, he formed a series of health-care companies. Some of his designs for surgical masks and plastic catheters still are used in hospitals today. In 1980, Sorenson sold his medical-device company to Abbott Laboratories for $100 million of Abbott stock. He kept the shares and profited greatly as they soared.

As a Mormon, Sorenson belongs to a faith that places great emphasis on family history, sometimes with the goal of posthumously baptizing ancestors. For most of his career, though, genealogy seemed too humdrum to command his attention. His wife, Beverley, took the lead, filling their home with pictures of their 47 grandchildren and various forebears. In an interview, she proudly noted that she is a descendant of John Taylor, leader of the Mormon church in the 1880s.

Eventually, Sorenson's views changed. "The older you get, the more you feel connected with those who came before," he says. "You even start to hear your dad's voice when you speak."

In the 1990s, Sorenson helped relatives develop charts of his forebears as far back as 15th-century Switzerland. He got his feet wet in the genetics business by acquiring a DNA-testing service called GeneTree in 1997, focusing on paternity issues. And he befriended Woodward of Brigham Young University, who was analyzing sheepskin DNA in ancient parchments. "I told him, 'Scott, why don't you study people instead?' " Sorenson recently recalled.