A JOKE MAKING THE ROUNDS IN HOLlywood: the sequel to Ellen DeGeneres's best seller, ""My Point ... & I Do Have One,'' is going to be called ""My Sexual Orientation ... & I Do Have One.'' Ever since word leaked out that DeGeneres's character on her ABC sitcom, ""Ellen,'' might come out as a lesbian, there's been much published speculation about whether the real-life Ellen also is gay, and might follow her alter ego out of the closet. All of which raises the bigger question: is TV ready for a same-sex sitcom?

It would be a radical move, one not even veteran staffers on the show saw coming. According to a well-placed industry source, DeGeneres has long wanted to ""out'' her character, Ellen Morgan, but held back while her show was still struggling for viewers. When she convened the first writers' meeting of the new season--at her home--she said she had an important plot development to announce for the coming year. The writers, almost all of whom are straight, were told that Disney brass had signed off on the idea of Ellen as a lesbian. (Disney, ABC's parent company, also produces the four-year-old sitcom.) They were instructed to keep the new twist under wraps. ""It was top, top secret,'' the source says. So much so that in storyboards drawn up to plan the arc of the series, NEWSWEEK has learned, the lesbian revelation was coded ""Ellen gets a puppy.''

DeGeneres refused interview requests from NEWSWEEK. ABC and Disney are also issuing nervous ""no comments.'' On the New York talk-show circuit last week (Dave, Conan, Rosie) the perennially pantsuited comedienne sidestepped the gay question with the gag that Ellen was ""Lebanese.'' To further confuse the issue, on ""Good Morning America'' she pretended to slip a male stagehand her phone number. (Although gossips noted that she brought a female date to the Emmys.) Hints at the fictional Ellen's sexuality--which has hitherto been pretty much nonexistent--will be equally coy, according to scripts leaked to TV Guide. One future episode has Ellen emerging from a closet and saying, ""Yeah, there's plenty of room, but it's not comfortable.'' And in this season's premiEre, Ellen sang, ""I feel witty and pretty and ... hey!'' But on last Wednesday night's show, the only sexual innuendo involved Ellen's strictly hetero cousin.

Floating the concept of a gay Ellen may simply be a trial balloon to test viewer and Madison Avenue's reaction. Ad buyer Paul Schulman, who tells sponsors which shows to buy air time on, thinks some of his clients would be turned off by a sitcom built around a lesbian character, particularly one broadcast at 8 o'clock. ""The movie companies won't be concerned, but packaged-goods companies [like Procter & Gamble] will. This is definitely not gonna help sales.'' When Mariel Hemingway kissed Roseanne in a lesbian bar, ABC moved the show from 8, the so-called family hour, to 9:30, a more adult time slot. NBC, on the other hand, kept ""Friends'' at 8 when Candace Gingrich (Newt's gay half sister) officiated at the wedding of two lesbian characters on the show. No public out- cry ensued.

Gay secondary characters are now a commonplace on TV; there are 22 of them, including a gay activist (played by Michael Boatman) on the new ABC series ""Spin City.'' Behind the camera, gay writer-producers run some of TV's biggest shows. The lesbian couple on ""Friends'' was inspired by close friends of executive producer Marta Kauffman and her openly gay producing partner, David Crane. And a recent Los Angeles Magazine cover story argued that the gay sensibility has permeated virtually all of prime time. Check out the bitchy banter between the ambiguously heterosexual brothers played by Kelsey Grammer and David Hyde-Pierce on ""Frasier.'' Still, a lesbian lead on a sitcom would be something new. And potentially risky. There have been enthusiastic votes of support posted on the Disney Web site. Ratings have dipped slightly, though probably more because of new competition from CBS's ""The Nanny'' than anything else. But DeGeneres is getting hate mail from viewers promising never to watch again. Will Disney stick by its star? Famously allergic to public scrutiny, the wholesome conglomerate has already come under fire from Baptist church groups over its policy of extending benefits to gay employees. The Rev. Donald Wildmon and his boycotting crusaders announced that ""advertisers will have to make a choice: either withdraw their support of the show or reveal their true allegiances to themes that gnaw at traditional family values.'' If Disney starts to feel burned by too much PR heat, Ellen may not get her puppy after all.