Ricky Durham founded Prescription 4 Love in 2006, inspired by his late brother Keith, who lived with Crohn's disease for 15 years before passing away in 2004. Though he doesn't find it appropriate to be a member of a community he founded, he says he can empathize with his members.
"He was a good-looking boy, and he could find dates, but when do you tell someone you have a colostomy bag? "It's nice to find someone who's going through what you're going through," he says.
Both sites require members to disclose their illnesses upfront, clearing the air for what might be a deal-breaking revelation later.
As one of its first members, he should know: He met his wife, Lynn, at a Date Able Valentine's Day party in 1988.
"I didn't want to try it," says Watson, who has moderate cerebral palsy and was working as a national project director for the United Cerebral Palsy Association at the time.
Love For Less Niche sites are also a lot less expensive.
Prescription 4 Love, which started charging in May 2009, is $9.95 per month, while most of the features on No Longer Lonely (including the dating service and chat rooms) are still free.
All of these can make dating -- often an ego-shattering minefield for those in perfect health -- even trickier.
"On bigger dating sites the competition is tremendous," says Jim Houran, Ph D, a clinical psychologist and columnist for Online Dating Magazine.
People with mental health problems, from chronic depression to schizophrenia, have also benefited from specialized sites.
Jim Leftwich, 39, a college librarian from White Plains, N.
"But I probably knew everybody in my community and nobody I knew wanted to date me or vice versa.
Lynn lived 60 miles away, but we made it work." By pushing a "friends first" concept, which has been emulated in the communal blog and forum features of Prescription 4 Love, No Longer Lonely, and other illness-specific sites, Date Able members can get up to speed on the dating world in a familiar environment without the prying eyes of the Web.
Y., has lived with schizoaffective disorder, a condition that combines features of schizophrenia and mood disorders (such as depression), since 1992.