Among the 10,000 people in the U.S. diagnosed with leukemia, lymphoma or other life-threatening blood illnesses each year, black people have the lowest chance of finding a donor for a bone marrow transplant.

"I call it the genetic powerball," said Jennifer Baird, an account executive for donor recruitment at the National Marrow Donor Program's Be the Match registry. Though the registry has 10 million potential donors, only 7 percent are African-American. Black patients have a 66 percent chance of having a good and willing donor on the registry, compared with 72 percent for Latinos, 73 percent for Asians, 82 percent for American Indians and 93 percent for whites.

To increase the pool of black donors, Be the Match has declared July African-American Bone Marrow Awareness Month. It's holding donor drives to collect cheek swabs (go to www.bethematch.org/join to see where), and has launched a website, www.swabplusdna.org, to educate people about the donation process and dispel fears that might keep people from signing up.

Though the traditional bone marrow extraction process, which involves inserting a needle into the pelvic bone under anesthesia, is what people associate with donating, in fact three-fourths of donations are through a less invasive procedure where peripheral blood stem cells are removed from donor blood, which is then returned to the donor through the other arm. After either procedure, marrow and stem cells regenerate within the donor.

People can also help by donating their babies' cord blood, collected from the umbilical cord and placenta immediately after birth. Doctors request cord blood in 21 percent of transplant cases.

Just 1 in 40 people who register ever gets called to undergo more tests; 1 in 540 goes on to donate.

Given that African-Americans are far more likely than other ethnicities to have sickle-cell anemia, which a marrow transplant can cure, the need is pressing, Baird said.