THE ARTS: Straight actors in gay roles are set to sweep the Oscars, but for the real gay actors, it seems Hollywood's closet is staying firmly closed, writes Philip Hensher

This might well be the Year of the Gay at the Oscars. Not the year of the gay actor - heaven forbid - but the year when actors are rewarded for playing gay parts. Philip Seymour Hoffman has produced what is said to be a virtuoso account of Truman Capote's mincing style in Capote. Felicity Huffman, the put-upon one in Desperate Housewives, has been persuaded to play a male-to-female transvestite in Transamerica. And Annie Proulx's great short story, Brokeback Mountain, about an extended and tragic love affair between two cowboys, has been filmed by Ang Lee, with Heath Ledger and Jake Gyllenhaal in the leads.

Oscars surely await some of these. There are half a dozen other big-name actors playing gay roles this season, and it's evidently now a safe career move. It's worth noting, however, that none of these actors themselves is gay, and indeed most have been at some pains to distance themselves from any such suggestion. Michelle Williams, the mother of Ledger's child, appears in Brokeback Mountain as his character's betrayed wife. That, one must assume, could only happen when there was no possibility whatever of it being, for instance, a sardonic joke on a real-life gay affair. The casting of Williams is a spectacular example of the sexual alibi; for anyone who cares to wonder, we are reassured that this could only be a piece of "let's pretend".

As if that wasn't enough, the actors in these films are always at pains to stress the incredible trauma involved in having to pretend to kiss a person of the same sex in front of cameras. To be fair, this is always a subject that unhealthily obsesses interviewers, but actors' responses are often highly amusing. Jake Gyllenhaal has said: "Heath and I were both saying, 'Let's get the love scenes over as fast as we can - all right, cool. Let's get to the important stuff.'" We are left in no doubt. The actors are so extraordinarily heterosexual that playing gay presents them with incredible challenges. Personally, I've spent a day down a working coal mine, and think that, as jobs go, being asked to snog Heath Ledger is not among the world's more demanding professional tasks.

But Hollywood, evidently, agrees with the actors. When you look at recent Oscars, the tendency is clear. Tom Hanks - famously uxorious - won for playing a gay man in Philadelphia. Hilary Swank's burlesque turn as a transsexual teen in Boys Don't Cry followed, and then Charlize Theron won for the fat, ugly, lesbian serial killer in Monster. Of course, some of the Oscar-winning credit goes to the make-up artist here - golly, look at Charlize, she's made herself all ugly - but most of it is surely down to the incredible fact that an artist was prepared to demean herself enough to play a lesbian.

When you look at the history of Oscar-winning performances, Hollywood's new enthusiasm for embracing minorities seems less than profound. Notoriously, the easiest way to win an Oscar is to play somebody bravely fighting a physical condition or a mental handicap. The easiest route of all, in fact, is to play a gifted artist suddenly struck down by disability - the early years of the Academy awards are littered with long-forgotten tales of deaf sopranos and ballerinas with gout.

As the "Kate Winslet" character in Ricky Gervais's series Extras scabrously observed, "Daniel Day-Lewis in My Left Foot? Oscar. Dustin Hoffman, Rain Man? Oscar. Seriously, you are guaranteed an Oscar if you play a mental."

The way Hollywood is rushing to reward heterosexual actors playing gay roles does not, really, reflect very well on its engagement. It is just too much like its fairly disgraceful engagement with mental and physical disability, and too much like rewarding a variety turn. Hollywood, so admiring of an actor's ability to project a sexuality not his own in these cases, has never been in a hurry to reward those far more common examples of gay actors convincingly playing heterosexual roles. In most cases, that involves rather more than the requirement of kissing this year's starlet in front of the cameras - a requirement no less or more demanding for a gay actor than Mr Gyllenhaal being asked to kiss Mr Ledger, surely.

One of the striking things about this curious fashion is that not one of the actors involved is gay. It seems fairly likely, in view of the tone of the attendant publicity, that a studio just wouldn't cast a gay actor in one of these roles. It is quite impossible to imagine Heat magazine asking a gay actor how they enjoyed kissing their straight co-star, or indeed, their gay co-star. It would raise questions of enthusiasm which the world of publicity is not quite ready for and we can only, it seems, watch such kisses with the assurance that nobody involved could possibly have derived pleasure from it.

But there's another, rather bigger reason why the studios wouldn't cast a gay actor in such a role. In America, evidently, there aren't any gay actors. One may grow rather satirical on the subject, but the truth is that whereas in every other country in the world it is widely accepted that theatre and film offer a congenial and sympathetic area in which gay men and women can work, this is simply not true in America. There are no gay actors - or at least, there weren't until Nathan Lane, to everyone's utter incredulity, came out. Of course, there were gay actors in America's past - James Dean, Cary Grant, Dirk Bogarde, Rock Hudson, Danny Kaye. Plenty of them, in fact. But, for whatever reason, there's hardly a single gay actor of recognisable stature working in Hollywood. An incredible fact.

Sooner or later, one of those non-existent gay actors will take a role as a gay character, and tell us all subsequently how difficult they found it kissing their co-star, to general derisive hilarity. In fact, it's not hard to think of a recent film where exactly that situation arose, starring one of those gentlemen with a boyfriend on the payroll and a lady hired for the purpose of premieres. But Hollywood will only seem truly tolerant when it allows gay actors to play gay roles, kissing included, and no whining about it in the publicity afterwards. Until then there's - how should one put it - a slight air of Al Jolson about the whole business.