MAKE a serious film drama about a physically or mentally disabled or disadvantaged person and Hollywood will hand you an Oscar for your trouble. Make a comedy about the same person and you'll receive nothing more than accusations of peddling poor taste and exploiting the less fortunate.

The history of the Academy Awards is littered with actors and actresses who've collected prizes for looking ugly or physically different to what passes for the norm on screen.

Such matters are no laughing matter, according to producers. Not so much for fear of offending those who are different, but because they think audiences prefer their stars to be ready, willing and able to be glamorous and like everyone else.

No wonder the Farrelly brothers, well known in the industry as brokers of bad taste comedies, took ten years to get their latest movie, Stuck On You, in front of the cameras. A comedy about conjoined twins was not an easy sell despite the success of their previous gross-out movies like Dumb And Dumber, Kingpin, There's Something About Mary, Shallow Hal, and Me, Myself And Irene.

These are comedies that have featured taboo-breaking comic episodes involving private parts and bodily excretions. They helped promote a whole raft of gross-out comedies such as American Pie, Road Trip, and Scary Movie in which no un-PC joke was left unturned as semen was mistaken for hair gel, mom's apple pie became a sex aid and pubic hair decorated a wedding cake.

Despite their films collecting a billion dollars at the box office, the idea of Peter and Bobby Farrelly's conjoined twins comedy was as welcome as Princess Anne's dogs at Crufts. "For the first five years we pitched the script, everyone was terrified of the concept," admit the Farrellys.

'Over the years, people gradually warmed to the idea but, for one reason or another, the timing was never right for the film to come together until now."

Matt Damon and Greg Kinnear play Walt and Bob, the twins ("We're not Siamese, we're American," they insist) who go looking for fame and fortune in Hollywood. At least, Walt does. He wants to be an actor. Bob has no choice but to go along with him. The comedy has been made, as Kenny Everett might have said, in the best possible taste. Rather than be accused of being un-PC, it could be said, with more justification, of not being funny enough.

The Farrellys, as writers and directors, know exactly how far they will go for laughs. "What's too far is when you make a joke or a comedy and somebody gets hurt," says Bobby. "We don't think Stuck On You is too far. There are conjoined twins in real life, and we felt we could tell a story about them as long as they aren't the brunt of the jokes.

"They are heroes, these guys, we love them. They aren't victims. They don't see being joined as a great difficulty at all. They've turned it to their advantage. We admire them."

It's a valid point - and one they've insisted applies to all their comedies about people who are different. The audience is invited to laugh with the twins, not at them. It must be healthier than watching You've Been Framed on TV, where viewers constantly laugh at others' misfortunes. In Stuck On You, the brothers don't take the mickey out of the twins. The people around them are the ones made to look ridiculous and foolish.

Kinnear says one of the things he responded to in Walt and Bob's story was this positive attitude. "The fact of the matter is it was clear they had great love for Bob and Walt, felt very strongly they were wonderful and they were the guys you were rooting for," he explains.

"The spirit of the movie is very positive. The disability is secondary to the part of just getting on with your life and meeting your challenges. The people around them have a bigger problem in some cases than they do, which is the case in life too sometimes."

The brothers often use real-life less able people in their movies. That wasn't possible for Stuck On Your - Kinnear and Damon were joined by an elaborate set of harnesses - but they did recruit real conjoined twins to be consultants on the picture. "We wanted to make sure we weren't doing anything that wouldn't be realistic for them to do," says Bobby.

"They lead a life like the guys in the film. They are conjoined at the head. One wants to be a country and western singer, so her sister goes to the recording studio with her. The other works in a hospital, so the singer goes to work with her. It's a fascinating story."

The Farrellys complain that Hollywood doesn't mind putting mentally retarded or disabled people in movies, as long as it's not a comedy. Forrest Gump, Rain Man, and My Left Foot are among the long list of such dramas that have done well, both critically and commercially. Yet schizophrenia support groups complained about the Farrellys' Me, Myself And Irene in which the split personalities of Jim Carrey's character both fought over the same girl.

It would be a poorer cinematic world, after all, if we were given nothing but feelgood romantic comedies and harmless slapstick comedies. Damon acknowledges the brothers "live on the edge a little with their humour" but doesn't see anything wrong in that. Kinnear also respects their treatment of what's "obviously a very tricky subject matter", believing they would never be maliciously, intentionally mean.

"They've dealt with this kind of material before and they've kind of gone to the line and straddled it a bit. I knew they would deal with this right and it would be coming from a good place," he adds.

Producers will be monitoring keenly the reaction to Stuck On You, which took $9m in its opening weekend in US cinemas. Gross-out films have gone out of favour in the past few years, with films like incest comedy Say It Isn't So failing to pull in big audiences. They never fully recovered from Freddy Got Fingered featuring Tom Green in episodes involving elephant sperm, drinking cow's milk straight from the udder and draping himself with the organs and bloody pelt of a dead deer. This was considered by audiences and critics alike to be too gross for words.

Whatever the fate of Stuck On You, the Farrelly brothers won't be going on to make sweet, charming comedies. They're already filming their next potentially-tasteless movie called The Ringer. Jackass prankster Johnny Knoxville stars as a man who tries to fix the Special Olympics.

Amazingly, you might think, the organisers of these games for disabled athletes have given the movie their backing and helped with the filming. "We send them the script and they really liked it because you get to see all these different guys in different lights and laugh with them," says Bobby.

* Stuck On You (12A) is now showing in cinemas.