Howard Brown is a healthy man. He has a wife and an 18-month old daughter. He weighs 185 pounds and has a full head of hair. And he knows just who to thank for all of it. His twin sister.

Ravaged by lymphoma in the late 1980s, Brown wasted down to 130 pounds. Aggressive chemotherapy and full-body radiation treatment left him in a weakened state and completely devoid of head and body hair. His chances of survival hovered at less than 50 percent. Yet a bone marrow transplant from twin sister Cheryl Brown-Gingras saved his life.

For ethnic and racial minority groups, finding a suitable bone marrow donor is particularly daunting, as Jews, blacks, Latinos and others are underrepresented among donor pools.

While Brown is fortunate enough to have a twin — who had a 65 to 70 percent chance of providing an acceptable match — most people don't. That's why Brown moved to invite Gift of Life, the Jewish bone marrow registry, to next weekend's UJC Young Leadership Western Regional Conference in San Francisco.

"It's like hitting the lottery. It's like hitting the lottery for someone in need, someone who needs a lifesaving cure," said Brown, 36, the co-founder of San Mateo-based PlanitJewish.com and an organizer of the conference.

"When you don't know the recipient and the recipient doesn't know the donor, it's one of the very highest acts of giving."

Jews roughly between the ages of 25 to 45 can register online for the conference, to be held Friday, March 7 to Sunday, March 9 at the Westin St. Francis Hotel. The conference is sponsored by the United Jewish Communities, the umbrella organization of the nation's federations, and hosted by the Young Adults Division of the S.F.-based Jewish Community Federation.

Thanks to a donation from the S.F.-based Jewish Community Endowment Fund, Gift of Life will be able to register up to 200 Jews free, both at the conference and at Congregation Emanu-El and Jewish Family and Children's Services of Sonoma County in Santa Rosa.

Founded in the early 1990s to find a bone marrow match for Jay Feinberg, Gift of Life has registered 72,000 Jewish potential donors and encouraged 150,000 others to register with other organizations. More than 500 transplants have been facilitated, including one for Feinberg, who is now the organization's executive director.

"Tissue type is inherited like the color of eyes and hair. The best chance to find a match lies with those if similar ethnic and geographic ancestry," said Feinberg, 34, whose organization is based in Boca Raton, Fla.

"If you're Jewish, that's not enough information for us to target an effective search for the patient. We need to know something more specific, where your ancestors were from. We use a lot of this information because Jews are not as well represented in the international donor pool as other ethnic groups."

The process, which takes only a few minutes, no longer requires a blood sample, and is instead conducted with a "buccal swab," a Q-tip-like device used to sample the buccal cells in the cheeks.

Donors who are not able to register free next weekend can obtain a buccal swab at giftoflife.org, where processing costs involve a $150 donation.

"It's life-altering in that a lot of our donors are affected emotionally," said Feinberg.

"It changes your outlook on life, you're really more appreciative of life."

Brown knows what this is all about — especially when he looks at his daughter.

When he was unsure how long he would live — and prior to the extensive radiation treatments that rendered him sterile — a doctor talked Brown into making a donation to a sperm bank "just in the off-chance you're going to make it through."

It may have been the best decision he ever made.

"She's a frozen kidsicle," jokes Brown about his daughter, Emily. "She's a miracle."

After the conference ends on Sunday, March 9 Gift of Life will register members of the general public from10 a.m. to 3 p.m. at the JFCS of Sonoma County, 1360 N. Dutton Ave. Suite C, Santa Rosa and 1 to 5 p.m. at Congregation Emanu-El, 2 Lake St., S.F.