When he first saw Anne it was in 30C Kenyan heat and he was drawn to her tall, slender frame, her smile and that flicker in her eyes. Norman made her laugh with a bad joke after noticing her callipers. Though his humour was a little off-colour they talked all night, and by sunrise this encounter - 10 years ago at a charity-work barbecue in Machakos, Kenya - was the start of a traditional courtship between two very different people: a black disabled teacher from western Kenya and a white ex-miner from Newcastle.

They were living 300 miles apart, volunteering in disadvantaged schools. With no telephones, they would send each other love letters, and when they were together, they slept in separate rooms. Once married, their romance would see Anne Wafula Strike become a Paralympian wheelchair-racer, a model, a motivational speaker and, perhaps most significantly, a mother.

Anne developed polio as a baby after being given an out-of-date immunisation. This affected the development of her legs, which meant she had to use crutches and eventually a wheelchair. The couple now live in Harlow, Essex, with their eight-year-old son, Timothy. Norman sees Anne as many things - inspiring, strong, bossy, sexy, but never as disabled. He's proud of his wife for all she's achieved and now recognises that flicker in her eyes when they first met as the look of determination. "She went into a wheelchair after a difficult pregnancy," he says. "She took up wheelchair-racing to get rid of her tummy fat and then turned pro. She's an incredible woman."

Anne won five gold medals at the Disability Sport England Eastern championships in 2003 and became the first-ever wheelchair-racer from East Africa to compete in the 2004 Athens Paralympics (where she was awarded a special gold medal for her achievement); in 2004 she was also voted Kenyan Sports Personality of the Year. And she models for VisABLE, an agency representing disabled models and actors.

Norman, 57, now a secondary-school supply teacher, believes it's their disparate backgrounds that make their relationship work. She's a Christian and teetotal; he likes a drink and a smoke. She went to university; he went into coal-mining.

Anne, 39, agrees: "The secret to our passion is capitalising on our strengths and differences; we'd never want to change each other. Love can move mountains. I love him for who he is, not what he is. He could lose a leg, an eye - it would still be the same. We know what real love is."

Norman's light-heartedness is a good foil for Anne's determination and eases her pain when her health is bad. "When things are really hard, he cracks a joke and then they don't seem so bad."

But it wasn't always easy. As a teenager Anne wanted to wear miniskirts and high heels but was conscious of her thin legs being disproportionate to her 6ft frame. She only caught the eye of the opposite sex when she was sitting down. "And in Africa, being a woman and disabled is so difficult. Women aren't equal, and those with disabilities aren't expected to marry." Later, when she was going out with Norman, African women would assume that he was only dating her out of sympathy and would throw themselves at him, thinking they were in with a chance. "If it had been just sympathy, it wouldn't have lasted as long as it has."

Anne knows that their bond is a solid one.

"We're fully committed to each other, and our marriage is a bed of roses. It has beautiful red petals and, like all relationships, thorns that prick." But she has had to learn to be confident. "I learnt to love myself before I could be loved by someone else," she says. Today she likes to feel sexy and admired by her husband, to dress well, to be surprised and taken out for meals. And this confidence transfers to the bedroom. "Sex for us is meaningful and passionate. We're upfront and totally honest about it with each other. It's sacred and not to be taken for granted."

Anne is aware that such trust and intimacy are qualities that more able-bodied couples often struggle to achieve, and she believes that her physical limitations may actually be an advantage in her love life.

Similar sentiments were expressed by Lesley Childs, a campaigner for disability rights who died aged 56, having suffered from juvenile arthritis since her youth.

"Disabled people make the best lovers," she said, "because we're experienced at asking for what we want in a nice way. We have to become ingenious at finding ways around problems and barriers."

So can disabled couples teach others anything about relationships and sex? The experts certainly seem to think so.

The sex therapist Dr Tuppy Owens says that many disabled people struggle for years to find a partner, so they treasure their relationships and enjoy them when they eventually find one. There's pressure on the able-bodied to spend their energies having unnecessary cosmetic surgery, whereas the disabled are encouraged to accept their bodies and feel comfortable with themselves: this can give confidence and lead to experimentation in all areas of life.

"Take someone with cerebral palsy," Tuppy says. "They may have jerky body movements in bed, so rather than focusing on orgasm and intercourse, they focus on other sensual pleasures you get from being in bed with another body."

Zoe Partington-Sollinger, 37, is a conceptual artist who works with disabled artists. Partially sighted herself, with three young children, she thinks those with impairments are often naturally creative at finding solutions to overcome their disabilities. "We think about things in different ways, on a different level," she says. "The way disabled people fundamentally approach life is different. Relationships have more value and meaning; they're about enjoying yourself and treating people with respect and dignity."

The actress and disability campaigner Julie Fernandez, 34, who has brittle-bone disease, agrees: "Disabled people have to be more creative during sex because their energy levels fluctuate. So they do it at times of the day when they feel at their best."

She adds that her own disability can be of help in sex. "My condition means that I'm double-jointed, which is handy in the bedroom. I can use yoga positions and stick my legs behind my head," she laughs.

The American photographer David Steinberg has had an intimate glimpse into the lives of the disabled, as he has dedicated the past decade to photographing them during sexual intercourse. "Probably the most significant thing I've learnt is that people can be wonderfully sexual in many ways. And that being fulfilled sexually is not particular to any one sexual act or sexual way of being. I've seen looks of unmistakable ecstasy on the faces of people who many would consider severely limited in what they can do sexually. And looks of profound love from people who cannot perform sexually in ways that most people consider absolutely essential to sexual happiness."

David's erotic photography began when he was encouraged to photograph disabled couples by sexual-rights activists in the States. He was approached by nine volunteers wanting to pose for him, whose disabilities included severe obesity and chronic pain, paralysis and cerebral palsy.

"Taking sexual non-fetishised images of people with disabilities can educate the public," he says. "It's a wonderful experience seeing yourself in a magical sexual place. My subjects are relaxed, and I have no expectations of what's supposed to happen."

His work has been displayed online at the sex-and-relationships website loversguide.com, and at sexologists' exhibitions in America.

His prints will also be featured in the book The Ultimate Guide to Sex and Disability.

The disability counsellor Shital Shah has found that relationships where disability has always been a factor have a higher chance of success than those where disability comes later in life. "We all have our flaws. It's just that disabled people's flaws are bloody obvious," she says. "It's common for couples who develop a disability to fall apart - 'in sickness and in health' goes out of the window. But for couples where it's always been there it's often genuine love. It's less superficial - it's about acceptance."

The author Mathilde Madden touches on a more uncomfortable truth about disability: the fact that the able-bodied are sometimes turned on by it. Her novel Equal Opportunities is about a woman who wants to have sex with wheelchair-bound men. "I met people known in the disabled community as 'devos', short for devotees. People are attracted to lots of things in a potential bedmate, some acceptable and mainstream, some more offbeat - like not being able to walk."

In the case of Michelle, 36, it was Andy Smith's bare feet that first caught her attention as he sat typing at a computer. "I have a thing for feet," she says. "His are very nice. I didn't know at the time that one of them was false. I just thought they were beautiful."

Andy and Michelle were at training college when they met in 2003. Andy, 47, had separated from his wife after losing his leg in a motorcycle accident and being confined to a wheelchair. He needed someone to talk to, and she enjoyed listening. When Michelle's marriage failed, their friendship led to romance.

Having learnt from the mistakes of their first marriages, the couple, from Sutton-in-Ashfield, Nottinghamshire, attribute the success of their relationship to good communication. "We tell each other everything," says Andy, who took up sailing after his accident and now competes nationally. "We say 'I love you' several times a day."

Michelle, a teacher, says: "I was sexually active when I was 15. Sex with Andy is the best I've ever had. We don't hold back, and no subject is taboo. I don't understand women who say they've never had an orgasm. Why don't they tell their partners? It's about communication - otherwise you can stay in a rut for 20 years."

Once married, the couple made a pact to lose weight, which led to them being crowned Mr and Mrs Slimming World 2008. Between them they shed 14 stone - a huge boost to their self-esteem and their sex life. "Body confidence helps with sex and with letting go, which in turn helps towards orgasm," Michelle says.

Sport is what brought Sarah and Barney Storey together. "Without sport we wouldn't have found each other," says Barney. Both are 31 and professional cyclists: Sarah, a Paralympian, was born without a left hand; Barney is able-bodied and a tandem pilot.

He was attracted by her outgoing nature and impressed by her skill as a cyclist. It helps that the couple appreciate each other's ambitions. "It's important being with someone who understands what you go through and that you need to focus," says Barney. And both regard sex as a matter of trust and fun. "Don't just assume what you think is right during sex," says Barney. "Talk about what you want and you'll both get more from it."

"Sex is about enjoying yourself," adds Sarah.

Another person who finds sex fulfilling is Dawn Gerrard, 23, a young person's development worker from Cheshire who is blind. In the absence of sight, she says, sex is often more sensual, with more touching, feeling and talking. "You shouldn't be scared to try anything in the bedroom. Blind people are often attracted to a tone of voice rather than looks, as well as a person's outlook on life. This can make relationships more meaningful."

Lee Pearson, OBE, who was born with twisted limbs, is a dressage gold medallist. Aged 35, he is openly gay and has never had problems attracting men, which he attributes to his confidence and good looks. But he is looking for a partner who is also a best friend, someone he can trust and confide in. "The disabled people I know aren't hung up on their bodies," he says. "They're more worried about getting a spot or a wrinkle. They can't change their frame or limbs, and are stronger people for that."

Dr Belinda Brooks-Gordon, a psychologist, notes that nurses and doctors too often assume that disabled people don't have sex, or they feel embarrassed about broaching the subject. "Attention is paid to providing for other physical needs, such as toilets that wash and cleanse," she says, "but not to considering how to fashion a vibrator for someone who has lost their arms, for example."

This strikes a note with Dominic Webb, 44, who was paralysed from the neck down in a car crash 14 years ago. He has accomplished great things since the accident, not least of which is becoming the first man on a ventilator to finish the 10-mile Great South Run. A tetraplegic, he competed in a chin-controlled electric wheelchair.

Despite needing 24-hour care, he's the chairman of DisCass, a citizens' advice bureau for disabled people, and is head of the Surrey Access Group. He's also a keen sailor, skier, oil painter, poet and blogger. One thing he would like to add to his life is a sex life.

The spinal-injuries unit where he was treated after the car crash pretty much told him to give up on sex. For years he pushed the subject to the back of his mind until one day his luck changed: he met Sue Newsome, a glamorous Tantric-sex worker from Stroud. She gave him a 45-minute sensual head-and-neck massage - these are the only parts of his body in which he has feeling - at his house in Godalming, Surrey. It was the first time in years that he'd been touched in a non-medical way.

First, they agreed the ground rules: Dominic would be the one in control and they would maintain eye contact at all times. Sue put on soft music and started to run her fingers through his hair. She massaged his head and stroked his chin, temples and lips. She blew into his ears and mouth and down his neck as she explored every part of his face. She floated a piece of silk over his skin and tugged playfully at his hair.

Dominic came alive: "I felt things I never thought I would experience. It was like someone was touching and stroking my whole body. It was relaxing as well as stimulating and really gave me pleasure. When Sue told me she would make love to my head, I was sceptical. But now I'm converted. It was really quite extraordinary."

This was new ground for Sue, too. At 47 she has more than 10 years' experience in her field. She was named Sex Worker of the Year at the recent Erotic Awards, and is co-founder, with the spiritual healer Hilly Spenceley, of the Shakti Tantra school. It was the first time, however, that she had taken on such a profoundly disabled client.

"Dominic is very intellectual, and for me it was important that he was the one in control. This was about exploration and I wanted feedback from him. Dominic's level of disability is extreme. But he was open to it and had a clear desire for it. And it felt really beautiful and sensual. It felt like I was touching all of him. I could feel my energy building - it was hair-raising." Follow-up sessions might be more explicit, Sue explains. "I could make it visually erotic, with sexy underwear, or Dominic could watch a woman touching herself."

Dominic and Sue were introduced by Tuppy Owens, 64, the sex therapist mentioned earlier. Tuppy believes there should be research into the role that Tantra - in which ejaculation is not considered important and may not take place at all - could play in tetraplegia. The session not only gave Dominic pleasure, she says, but lifted his confidence and relieved his muscle spasms. "This is ground-breaking stuff."

Tuppy says there is a common misconception that people paralysed below the waist cannot have an orgasm. But research has shown that when parts of the body lose sensory function, the brain turns up the volume elsewhere. "You concentrate on stimulating the areas above the paralysis. This could be the wrists, neck, nipples, ears, all of which can be extremely erotic. Playing with these areas, whether it's with sensual oils or vigorous vibrators, can sensitise them further, leading to orgasm. But it takes practice.

"People differ a lot, sexually. Some are able to reach orgasm entirely through the mind."

Part of Tuppy's job as the founder of Outsiders - an organisation that helps disabled people find love - is to provide a voluntary sex-and-disability helpline. She also puts disabled people (at their request) in touch with responsible escorts through her website Tender Loving Care. But paying for sex is still a taboo area for many.

It's also controversial legally. Tuppy's work could be affected by recent Home Office proposals that would make it a criminal act for men to pay for sex with a prostitute controlled by a pimp. The disabled, says Tuppy, would be the first victims of the new legislation, which could be in place by the end of this year, as it would discourage them from using sex workers.

Tuppy, who qualified as a sex therapist at St George's Hospital Medical School and founded the Sexual Freedom Coalition as long ago as 1996, points out that sex workers can be of particular help to those with spinal injuries who cannot reach parts of their body that still have sensation, although this specialised sex work is still not recognised by spinal-injuries units.

She has aired her views in a government consultation paper and intends to launch advice packs on the Outsiders site to explain how simple it is to advise disabled people on sexual matters by pointing them in the direction of helplines, internet forums and specialist dating agencies.

James Palmer, 50, a retired computer expert who uses sticks to walk and has never had a girlfriend, feels very strongly about the issue of paying for sex. "My life is ruled by sex - I'm a sex addict," he says. "I was at a party when I was 20 and I got glandular fever from a kiss. Two weeks later I was in a hospital bed, unable to move. I'd contracted encephalitis.

"I've found it bloody impossible to find a girlfriend, but I have 25 gallons of testosterone that I can't switch off. So I search the internet for porn and I've gone to sex workers."

He won't be deterred by changes in the law, he insists: "Well, they need to tell me which police station I should turn myself in to, because I'm not giving it up. Doctors say to be truly healthy we need sex once a week. Without sex workers I'd have no pleasure at all."

The International Union of Sex Workers' - which in spite of its name is a small London-based organisation with about 150 members - has made its opposition to the legislation the subject of a recent campaign.

Chris Student, an escort who is the union's secretary, says that if the changes become law, courses dedicated to teaching sex workers the special requirements of disabled people will probably be abandoned. "I specialise in female disabled clients and offer discounts," he says. "The law would stigmatise our work further. Disabled people are already a vulnerable group, and cloaking our work in further secrecy would be a mistake."

Dave Thompson, who runs one of the only sex-and-disability projects in the UK, has been astounded by society's ignorance. He recounts horror stories of health professionals telling people with catheters that they can't have sex and those with learning disabilities that they can't be gay because they don't understand sexuality. Paralysed himself following a sports accident in the 1980s, Dave, now 50, is working with occupational therapy students at a Liverpool University to address the subject. His project, Sex and Disability Matters, is small-scale and confined to Warrington.

"Our project is like a pebble in a lake. It needs to be nationwide. We educate people about things like dildos and vibrators. Sometimes they're considered tacky, but they can be vital to disabled people. It's frightening to hear the views of some health professionals. They've no qualms talking to disabled people about personal hygiene, or how to insert a tampon, or going to the toilet, but sex is hidden away."

Tuppy Owens is also challenging ignorance, planning conferences so that health workers can listen and learn from experts and from the sexual experiences of disabled couples. She has dedicated the past two decades to campaigning for sexual freedom, so it's perhaps fitting that she should have the final word.

"Disabled people feel at the bottom of the social scrapheap. It's difficult to feel good about yourself when you're dismissed by the medical profession, and social and health professionals don't speak about your sex and relationship problems.

"Once people know you can learn from disabled relationships, they become much more tolerant. While they continue to have closed minds about disabled couples having sex, and to be prejudiced against sex workers, they will never be sexually free in their own minds."