Learning disabled people do not have sex, so John Tattersall was told when he rang a medical centre in West Yorkshire to ask for contraception information for young people with special needs.

Tattersall, 47, who has a mild learning disability, was unsurprised by the statement which he heard two years ago when co-ordinating a sexuality project run by Leeds University and human rights charity Change.

"I'd like this prejudice to go away," says Tattersall, recalling that at his special school, teachers explained what sex was, "but never gave information about contraception".

Social integration for learning disabled people has improved since the 1960s when Tattersall was growing up, but attitudes towards sex and relationships have not caught up. Vivien Cooper, founder of campaigning family support organisation the Challenging Behaviour Foundation (CBF) explains: "It's difficult for families to access good information and resources – our experience is that it's not routinely offered and that it's postcode lottery as to whether it's good support or not."

The view that sex education is patchy – regardless of if pupils are at mainstream or special school – is reflected in the project report Tattersall worked on, Talking About Sex and Relationships: The Views of Young People with Learning Disabilities.

Ruth Garbutt, research fellow at Leeds University Centre for Disability Studies, recalls: "There was information for teachers but there was very little available for families and young people with learning disabilities. Even when information was available for teachers, teachers often didn't always know about it and weren't getting a clear steer from their local education authority."

Several of the 17 young people who took part in the project thought gay sex was illegal and did not realise that police investigate cases of sexual abuse. Parents and teachers revealed stories of young people being frightened by puberty – including a boy who had plucked out his pubic hair.

Part of the problem, says CBF's Cooper, is sexuality is a difficult topic generally. Cooper comments on sex education for learning disabled people, especially those with complex needs: "There are a range of issues with regard to capacity and consent to consider, as well as limited communication ability and communication methods – signing, symbols and so on. For individuals with severe learning disabilities, it can be difficult to equip them with understanding about socially acceptable behaviour, including sexual behaviours." The CBF offers information about difficult sexual behaviour.

So what sex and relationships education is available? One landmark teaching resource, Living Your Life, first produced in 1991, grew from a project led by learning disability expert, the late Ann Craft, at Nottingham University. Last year sexual health charity Brook and Nottingham-based specialist Oak Field School worked on a new edition. The 366-page resource includes worksheets and assessments.

The innovative Josephine Project in Newcastle-upon-Tyne is one interactive project which helps young learning disabled women to explore issues using a life-sized female model made of soft material, complete with reproductive organs and a "feelings bag" for discussing emotions.

Another positive teaching resource was produced by the children's learning disability nursing team in Leeds in 2009. Puberty and Sexuality for Children and Young People with a Learning Disability was developed in response to several referrals relating to sexualised behaviours in children with learning disabilities. The Family Planning Association also offers specialist projects for learning disabled people.

As Oak Field head teacher Stewart explains, more resources along the lines of this good practice is vital: "Denying access to appropriate education will make [a vulnerable population] even more vulnerable. They need to be taught to value themselves, to know that their bodies are important."

Leeds' Garbutt adds that such knowledge is a moral and social investment: "Investing in this now will leave young people with learning disabilities less open to abuse and also reduce the amount of unplanned pregnancies and – in the case of parents whose children are removed from them – reduce the number of looked after children."

Experts agree that work in this area lacks national consistency. Teaching formats must be tailor-made for learning disabled pupils and more information should be available for parents. Teachers should have more resources and training, links between schools and sexual health professionals should improve and learning disability sex education should have a higher priority on the national curriculum.

In addition, if people are to develop secure and loving relationships, they need more safe places to socialise. Brook chief executive Simon Blake says: "Like all young people, those with learning difficulties need social and practical opportunities for sex and relationship education to be applied: testing and understanding boundaries in personal relationships and experiencing love, romance and intimacy."

"People with learning disabilities have the same emotions and feelings as we all do," stresses CBF's Cooper, "but limited ways of communicating about these. Failing to support the person and their family appropriately can lead to situations where sexualised behaviours develop which are considered challenging – and this can in turn lead to all sorts of exclusions, restrictions and vulnerabilities."

Tattersall, married for 17 years, says that despite the lack of information at school, his parents supported him to have relationships: "My parents let me have a relationship as long as I was happy – a lot of young people on the Leeds project didn't have that opportunity."