Stand up to answer the question: how good are female comics?

They are foul-mouthed, brutish and nasty - and that's just the effete Oxbridge ones. But all may be about to change in the world of the stand-up comedian. For the first time in its history, the Edinburgh Fringe, the world's biggest arts festival, which starts tomorrow, has more than a handful of token female comics.

Forty-four are making the loneliest walk in show business - the few steps to the microphone - at this year's festival, more than twice the number who braved "ordeal by audience" last year. All will be battling the bizarre, age-old prejudice that women comedians are not that funny.

As stand-up Lucy Porter, who cut her teeth on working men's clubs around Manchester after leaving the Mrs Merton Show, said: "The minute you get on stage, arms start to fold. Every woman gets this - it's better than the heckling, which we used to get, but it boils down to the same thing, they don't expect you to be funny. I have lost count of the number of people - mostly other women actually - who have come up to me after shows and told me that they don't normally like female comedians."

So ingrained is the prejudice that Katherine Jakeways, one of the many female comedians making their Edinburgh debuts this year, admits wondering if the comedy chauvinists have a point. "I myself am often more suspicious when a woman stand-up walks on. It's automatic. I know it is wrong, but that feeling is out there. I think it is changing, but women have to work that much harder for the audience to like you."

The success of such genuinely funny and innovative TV shows as Smack the Pony only highlights the problem, she argues. "I wish it was seen as a good sketch show rather than a good women's sketch show. I mean, it is not as if guys have to deliberately come up with all-male shows."

Other than perhaps the Catholic priesthood, few professions are as unapologetically male as stand-up comedy. Dr Mike Lowis, a psychologist attached to University College Northampton, who has studied gender and humour, said stand-up fits the male need for display perfectly: "More men probably do stand-up because it is in their biological make-up to do so."

The very notion of a solitary male holding a room in thrall with nothing but his raw wit and animal magnetism has deep psycho-sexual roots. Similarly, the phallic significance of the mike is so obvious, Lucy Porter has dispensed with it. "The mike is a power thing you use to dominate your audience. It's phallic definitely, and I feel it gets in the way. The first thing you do anyway when you walk on stage is put the mike stand to one side. Women prefer more of a chat. That is why I am using a lapel microphone."

Even the conventions of the form have more than a whiff of the locker room about them, with the inevitable "dick joke" perpetually dropped in between 10 and 15 minutes into a set. Even Jakeways, who until last week was a travel reports presenter on GMTV, confesses to "giving in on that one ... But at least my dick jokes come from the consumer, user angle".

The legendary lone-wolf lifestyle of the late-night shows, later night drinking, casual sex, and a chip-butty breakfast on the National Express coach to the next venue, also help keep stand-up male-dominated, Porter insists. "It's not exactly the ideal environment in which to have a stable relationship or think about children," she said.

The laddishness even extends to the typical comedy bill. "Apart from at Edinburgh, you rarely see another female because two women will never be booked on the same bill," she said. "A woman, or a speciality act maybe, will always be sandwiched between two guys. I think they are afraid if they booked two of us we might start menstruating in synch."

In the past the women stand-ups who have broken through have tended either to be exceptionally talented, exceptionally stubborn, or the lesbian equivalent of the stand-up alpha males.

Most female comedians have preferred to progress via sketch shows and comedy duos rather than the one man and a microphone method favoured by males. According to Jakeways, it is safer to have characters to hide behind. "It's slightly less nerve-wracking for me, anyway. I think of myself as a comic actress, and I don't know if I want to put myself on the line. Male comics seem to have no trouble believing an audience will be interested in them but I could never be that sure."

With audiences and comedians themselves tiring of the conventional, confessional stand-up style, there has been a discernible shift to character comedy - a move that may account for the dramatic rise in the number of female comedians on the Fringe. (Men still, however, account for the vast majority of stand-up, with 150 odd strutting their stuff this year.)

Even such established stars as Jo Brand, who made her name when stand-up was raw and rough, are moving towards theatre. She is appearing in Edinburgh in a play called Mental, which purports to explain the difference between madness and insanity.

No one yet, however, has been able to explain the ever-expanding size of the festival, or the financial reasoning for taking a show there. On the Fringe alone there will be 1,541 shows put on by 12,940 performers, most of whom will probably lose money despite the record box office and attendance last year, when nearly a million people paid for tickets.

So big has the Fringe become - it attracted more punters than last year's Commonwealth Games in Manchester - that it is starting a week earlier this year. In all, it would take you four years and 143 days to see every performance.

Highs and lows

The good...

Napoleon in Exile at the Traverse theatre. Chris Goode, one of the most exciting young directors in the country, follows up his acclaimed Kiss of Life with a new tragi-comedy.

Only the Lonely at Roman Eagle Lodge. Kip Utton, whose one-man show about Hitler became an international hit, has struck gold again with this examination of a Roy Orbison tribute act.

The bizarre ...

Aaron Barschak, otherwise known as the comedy terrorist who gatecrashed Prince William's 21st birthday party at Windsor Castle, is urging the public not to go to his show, Osama Likes it Hot, at the Underbelly. Already this week he attempted to hijack a tourist bus to get into Edinburgh Castle.

And the grotesque ...

An unseemly three-way battle between Janet Street Porter talking about her life and career in her one-woman show All the Rage, Christine Hamilton appearing in the Vagina Monologues and "Doktor Death", Professor Gunther von Hagens displaying the bodies of dead babies to promote Corpus, a musical about his plastination method of preserving human remains.