Ten years ago, when she was 11, Robyn Steward was diagnosed with Asperger's syndrome, a form of autism that made that already challenging time particularly difficult. While other girls were forming tight friendships, hanging out with each other for hours after school, Steward had trouble fitting in with her contemporaries - more so, she suspects, than if she had been a teenage boy with the syndrome. "At that age," she says, "boys aren't connecting with one another so much, but for girls it's so cliquey. Also, the stuff I was interested in seemed even more weird in a girl than a boy. It was mostly computers and music with me - boys can get away with being a bit obsessive, but it seems more strange in a girl."
As Steward says, her situation was complicated by the invisibility of girls on the autistic spectrum and by the association of autistic traits - social awkwardness, for instance - with masculinity. The majority of autistic people are men, with four times as many males as females being affected, and the medical world is awash with theories about how the syndrome is connected to the wiring of the "male" brain.
In fact, when Hans Asperger first described autism in 1944, he initially believed that he had discovered a condition that only affected boys. As Asperger himself went on to realise, there are girls and women with autism, and more recently their numbers have been growing, along with the incidence of autism in general.
For these women, the diagnosis can be a double whammy. Not only do they have a disorder whose causes are unclear and the treatment of which is still controversial, but it is even less recognised in females. Women and girls tend to be pushed to the sidelines of any coverage of autism and Asperger's syndrome, their experience purged from the public eye, making those who experience the disorder even more cut-off and misunderstood than their male peers.
Because of this, securing a diagnosis, for example, can be difficult. Margaret Lambton's daughter Harriet, who is now eight, developed normally until she was about 13 months. "But then she stopped answering to her name, and stopped engaging with those around her, and I had a sickening feeling that something was very wrong," says Lambton. "To me it was screaming 'autism', but when I told my health visitor, she tried to reassure me.
She said autism was so rare in girls, it was very unlikely."
Unlikely, but not impossible. Harriet failed her two-year health check, and three weeks later Lambton was told that her child had severe autism, with the developmental profile of an eight-month-old. "Girls who have autism often have it very seriously, and that's the case with Harriet," she says. "She'll never live independently, and she'll never have a relationship or children when she's older. She's my only daughter, and one of the many devastating aspects for me is that we'll never have a normal mother-daughter relationship.
"I go on courses for parents of children with autism and there often isn't a single other parent of a girl," says Lambton. That is because, despite the fact that more girls are now being diagnosed, they tend to be diagnosed later than Harriet. At special schools, and in support groups, girls find themselves heavily outnumbered by boys.
"Around nine in 10 parents at the support group I help run are parents of boys," says Rose Edumijeke, whose five-year-old daughter has autism. "And all the groups we go to tend to be very boy-orientated. There's no shortage of football sessions, but my girl might like to try ballet or tap-dancing. She couldn't possibly manage that in a regular class, but I don't know of anywhere that runs special sessions for children with autism."
Dr Lorna Wing is a veteran psychiatrist who devoted her career to studying autism after her only child, Susie, was diagnosed with a severe form of the condition. She says girls on the autistic spectrum often appear "normal" at first meeting.
"They appear to be more social than boys with autism, but then you notice that their sociability tends to be inappropriate," she says. "They might go on and on talking about the things they are interested in, and they fail to notice that you're not remotely interested. They have a poor ability to 'read' people, and that's something that's often very highly developed in females."
This means that women with autism often struggle at work because they lack what is often taken for granted in women - the intuitive ability to understand where people are coming from and how to manage situations. Because of subtle sex differences, we tend to "expect" more of women in the workplace in terms of smoothing things over, of saying the right thing; and whereas we would excuse a man who lacked these abilities, we are subliminally a lot less forgiving of a woman who has similar shortcomings.
At facilities such as the Lorna Wing Centre for Autism in Bromley in Kent - named in tribute to Wing's contribution to understanding the condition - more and more women are coming forward for diagnosis who have struggled all their life to "fit in", and who, time and again, have found themselves wanting.
For women such as this, having their "oddity" validated, acknowledged and, to some extent, explained, can be life-changing. Selina Postgate, 53, always knew she was different: but it was only last summer that she finally found out why. "Knowing I have Asperger's syndrome has changed everything in my world," she says. "It's made me realise who I really am, and why I think differently."
If the diagnosis had come earlier in her life, Postgate believes she would have been a lot more successful. "I've never managed to do the things I've wanted to do," she says. "I've done very little with my life professionally and I could have done a lot more if I'd understood myself."
Nor would it have mattered so much, Postgate argues, if she had been born male - even undiagnosed, men with autism can live a life that is high-performing, acceptable and rewarding, she believes. "At school I was bright, but eccentric. If I had been a boy, that would have been tolerated more. I'd have gone into science, I'm sure - I might have gone on to be a nuclear physicist. I'd have met some girl who would have become my supportive wife and she would have made up for my social shortcomings, in the eyes of the world, and I'd have been the rather odd but brilliant professor who couldn't really handle social occasions but who was always well looked-after by his lovely wife, and who did so many wonderful things at work that none of it mattered anyway.
"Instead of that, though, I have achieved practically nothing. Relationships, like jobs, have gone out of the window - I've not had the self-awareness to hold down either.
Being an autistic woman has been pivotal to everything that's happened to me. If I'd been an autistic man, my story could have been very different."
Because autism has probably been underdiagnosed in women, and because study of the condition only stretches back a few decades, very little is known about how it pans out for women in later life. According to Wing, there are plenty of indications that the disorder is exacerbated by hormonal disruption - and while that has been documented around puberty in both females and males, less is known about what happens around the menopause.
In the case of Wing's daughter, the menopause was to trigger a worsening of her condition - with tragic results. "Susie had been through a bad time around puberty, and when she was menopausal it seemed to get very bad again. She started drinking more and more water - we knew it was dangerous, and we tried to stop her, but we didn't realise how dangerous it could be, or how much water she was drinking."
Two years ago, Susie's obsession with drinking water triggered a heart attack, and she died at the age of 49.
"I miss her so much," says Wing. "She wasn't like other people - when we went out we always got noticed and she always looked odd, but I was so used to it. To me she was just Susie, with all her funny little ways. I loved her very, very dearly."
Steward, though, is full of hope for the future. She understands her condition and is adamant that it gives her some advantages. Some women, she says, are just too focused on contact with other people and on the ins and outs of human relationships. "Relationships are important, but to be a really self-reliant individual you need to be the sort of person who can cope alone. I think autism gives you that self-reliance, and I think it makes me strong - it helps you know your own limits."
Another plus, says Steward, is that she has an unusually strong ability to focus on one clear goal. "It's part of the obsessiveness of autism, and it can make you very determined and that, in turn, can lead to success.
"I think to turn autism to your advantage you have to find your niche, and maybe a lot of women with autism find it harder to find that - but if you can, some of the traits of the condition can be advantageous - why else have so many geniuses been people with autism?".
An atypical girl writes ...
Just because you can't see women with Asperger's doesn't mean we're not here, says Bridget Orr
I am a girl with Asperger's syndrome. And if you thought that the sob story ended there, I'm afraid that there's more: my condition is inescapable, and four times as many boys have it. I rarely saw myself reflected anywhere in relation to the condition. The newsletters my mother received from the local autistic society always featured a blank but crying young boy. I used to go to special schools and classes that were dominated by rowdy and moody boys, and even the misconceived stereotype of people with autistic spectrum disorders is that of a humourless and awkward-looking nerdy man with an attitude problem. I am offended most by the "awkward-looking" part.
Like the girls and women featured in Joanna Moorhead's piece, I too have struggled to fit in with the mainstream and also the autistic subculture. No matter which school I went to, I would either feel frustrated by the chaotic mainstream world or suffocated by special schooling. Yet, I knew I wanted to live a normal and independent life like my big brothers and sisters, and not be dependent on my mother like the sons of my mother's friends.
I am still a normal young woman. Because so many of my experiences have been shaped by my condition, it is easy to forget that my life has also been shaped by society's expectations of girls my age. I am sure I would have loved reading, disliked school dinners and hated my teachers in any type of school, and I guarantee that all young people, autistic or not, are worried about their plans for the future and how to assert their independence. Feeling uncomfortable in one's skin is not just an autistic trait.
If there is one slight difference between my experiences and those of the "normals", it is my subconscious fear that losing a wallet or a mobile phone could set my personal independence back 10 years.
As much as it is hard to be a girl with Asperger's syndrome, it is still unimaginable what my life would be like if I were "normal". I would love being more confident around new people and assertive about my feelings and opinions, but surely these can be developed with time. I do not believe in autistic pride, but I would hate to lose my determination to take on new challenges and become more independent. Female "invisibility" in the autistic spectrum should be a feminist issue. For all the struggles with employment, family relationships and individuality that "normal" women face every day, we face these too - and more besides. You only have to look at the lists of famous people who, it has been speculated, were in the autistic spectrum - Isaac Newton, Ludwig van Beethoven, Albert Einstein, - to see how boys' autistic traits are synonymous, to some extent, with success. For girls like me who have been affected by autism, the challenge is to stand up for ourselves in the male-dominated world of the autistic spectrum, yet reassure ourselves that we are still normal girls.
· The National Autistic Society's helpline is on 0845 070 4004 (autism.org.uk).
