Jonelle Allen doesn't have any children and has no plans to become a mother. In her other life, though, as Doreen Jackson on the soap opera Generations, Allen is due to give birth any moment. Not only that, she already knows that her baby suffers from sickle-cell anemia, a genetic disease found primarily among blacks.

The incurable disease causes blood cells to change from round to sickle shape. The sickle-shaped cells have difficulty passing through the bloodstream without sticking and clogging, causing pain in many parts of the body. Sickle-cell anemia occurs when both parents have hemoglobin type S. About 1 out of 400 black Americans have the disease and 1 out of 10 carry the trait. Since sickle-cell anemia was introduced into the story line of the popular daytime television show, [which airs on WPTV and WTVJ, weekdays at 12:30 p.m.] Allen has become something of a spokeswoman for sickle-cell foundations around the country.

She will be in Palm Beach County Saturday, as honorary chairwoman of the Sickle Cell Foundation of Palm Beach County. Until Allen's character, sickle-cell anemia was one of the few diseases that hadn't made it into soap operas. In recent years the daytime dramas have involved their characters in all sorts of social and medical problems such as alcoholism, drug addiction and AIDS. Soap characters have had mastectomies, heart transplants and test-tube babies, but nobody had sickle-cell anemia until now.

"Generations, being the first daytime show that has a truly interracial cast, lent itself beautifully to that purpose," Rick Schrand, Allen's publicist said. As in most soap operas, Allen's character has a rather complicated past. The baby she is carrying was fathered by the son of her husband's business rival. She discovered the baby had sickle-cell anemia from genetic tests she took to determine the father of the baby.

"Some members of my family carry the sickle-cell trait," Allen said in a recent phone interview. "I don't have the trait, but I believe an aunt of mine does." Allen said she has learned a great deal about sickle-cell anemia through her work on the show. "There was a lot of misinformation out there about the disease and who could get it," she said. "For instance, I didn't realize that it occasionally occurs in some white people. So, I think the show is doing a real service. It is not only entertaining but educating and giving out the right kind of information."

As honorary chairwoman, Allen will speak at a luncheon at the Helen Wilkes Hotel honoring former West Palm Beach Mayor Eva Mack. A public health nurse, Mack pioneered testing for sickle-cell anemia among Palm Beach County schoolchildren. She also started the county Sickle Cell Foundation 17 years ago. At 2 p.m. Allen will preside at a dedication ceremony to rename the Sickle Cell Center, 1600 Australian Ave. in West Palm Beach, in honor of Mack.

AS THE creator of NBC's new soap "Generations" says, "At one time or another, almost everything has been done on the soaps. These shows haven't been on a long time for nothing." Nevertheless, Sally Sussman is trying something "a little different." "Generations," starting tomorrow, is the first daytime drama that's racially balanced. It's the first in which a black family is part of the show's "core" and not just a token afterthought.

What Bill Cosby did for prime time and Oprah Winfrey did for late afternoon, NBC is hoping that Taurean Blacque, Joan Pringle, Lynn Hamilton, Jonelle Allen and the other black cast members of "Generations" can do for soaps. Sussman, who labored on "The Young and the Restless" for five years, came to NBC a year and a half ago with her idea for a truly integrated soap. The white family, headed by Patricia Crowley, would be making a good recovery after earlier financial reverses. The black family would be headed by a woman who was the whites' former housekeeper. The black matriarch's son-in-law would be a dynamic businessman whose wife wants to buy back the mansion where she grew up.

The beauty of Sussman's idea, in her view, is that "as far as these characters' basic human drives are concerned, the blacks on the show could be white and vice versa. There are cultural differences that will be apparent, but the problems the characters will face and their flaws won't be 'black' or 'white.' "

Blacque, a onetime postal worker and recent veteran of "Hill Street Blues," plays the businessman whose chain of ice cream parlors has made him wealthy. He describes the show's situation: "The money the white family once had has now dwindled down, while our money dwindled up.

"My character has become very wealthy. It happens. It happened to me. Before you say that there aren't very many black people who have done what this guy did, look at me. I've invested. I own real estate, an apartment building. My income from acting is the icing on the cake.

Blacque smiles as he shows off a photo of himself and three of the six young children he has adopted and cares for as a single parent. This is a man who is in love with fatherhood, and now he gets to play a "giving, strong" father on TV for half an hour a day, five days a week.

Blacque and the rest of the cast had been shown only Sussman's first 10 scripts before they plunged into what will become a daily routine for a minimum of two years. Sussman and her co-executive producer Rudy Vejar know where the show's "bible" will take its characters, but the only thing Sussman will say for sure about the show's near future is that there won't be an interracial romance. "That's been done before, on four or five shows at least. On 'Generations' we won't exploit the obvious. That's not to say we can't have conflicts between black and white people - though not conflicts based on race. And we have some strong friendships."

The bedrock friendship on the show is the one between the onetime mistress of the mansion, played by Crowley, and her former housekeeper, Hamilton. When Hamilton's son-in-law, Blacque, needs a co-signer for a loan to start up his ice cream business, Crowley goes to the bank with him. Crowley has had top TV roles once a decade: "A Date With Judy" in1951-52, "Please Don't Eat the Daisies" in 1965-67, "Joe Forrester" in 1975-76, and now "Generations." She most recently was seen on "Dynasty." "I've never watched daytime television," Crowley says.

Many actors who don't work on soaps regard them as the lowest form of acting, suitable only for recent drama-school graduates or tired old war-horses. Crowley has a different point of view. "I want to work, and I have my work cut out for me here. When I was on 'Dynasty,' you could end up doing about one scene a week. You could go in at 8 a.m. and be finished at 10 ... Here we'll have four rehearsals in the morning, then a dress [rehearsal] before we actually shoot it in the afternoon."

Crowley's duty will be doubled if the show does well enough to expand to an hour from the start-up length of 30 minutes. SOAP actors are notoriously mortal. Crowley, however, is thinking long term. "I called my friend Anna Lee, who played my mom once, years ago. She's 75 and she's been on 'General Hospital' for 11 years. She said she loves it, and she'll play her character as long as they'll let her.

"I can't see into the future, but this looks like a nice, happy adventure." As Sussman says, "I just hope we'll be as successful as some of the so-called 'failures' in this field that have been running 10 years."