When Emma Claire Sweeney was a young girl her parents were told to put her severely disabled younger sister into an asylum, forget about her and focus their love on their two 'normal' children. This was as recently as 1984 revealing that the stigma of disability was still entrenched in society at that time.

Emma's sister Louisa was diagnosed with cerebral palsy and later on with autism. Both Emma and her other sister, Sarah - Louisa's twin, are grateful to their parents for ignoring the doctor's advice. Emma recounts her experiences and those of her sisters in her debut novel, Owl Song at Dawn.

"I realised that I hadn't read any novels that represented families like ours," says the 36-year-old from Hemel Hempstead. "There aren't very many novels that have characters with disabilities, especially not narrating and the ones that do tend to perpetuate stereotypes."

Owl Song at Dawn follows twin sisters Maeve and Edie Maloney, who were born in 1933 in Morecambe. One of them is feted as the cleverest girl in town and one of them is diagnosed - using the terminology at the time - as 'severely subnormal'. Both the twins narrate the story about how one incident affected both of their lives.

"I wanted to write something that celebrated people with all sorts of disabilities – looking beyond what society would usually value," explains Emma, who studied English Literature at the University of Cambridge.

"People assume that maybe if you have a sibling who has severe disabilities that you must feel resentful of the amount of attention your parents inevitably have to give them. But I think what Sarah and I found was that Lou gives a lot more than she takes - she doesn’t have many inhibitions so when you take her to a party she is the first on the dance floor and the last one off. And it kind of gives everyone else the confidence to shed their inhibitions too.

"One of the great skills she has is her capacity for happiness - she’s good at bringing joy into a room and bringing people together. So if she was in this café now, she would be introducing you to that gentleman over there and to the lady by the counter."

Emma grew up with her family in Birkenhead near Liverpool and despite it being a "happy town" as she describes it, her sister still faced some discrimination.

She says: "One time at a swimming baths a couple of boys started making fun of Lou - I was probably about nine-years-old at the time, and I had always been really short for my age - and I just suddenly remember acquiring this strength I didn’t know I had and I pinned these guys up against the wall.

"I think it probably made me and my other sister Sarah a bit fearless, because we would be prepared to stand up to bullies. On the other hand, as I have got older I realised that sometimes when you are trying to speak up on the behalf of someone else you can actually take away their own voice and it can be a bit of a controlling act on your part. So one of the things I have had to learn is to know when to step back and let them speak for themselves."

Going back to the novel, I ask Emma why she chose to set her novel in the 1930s and '50s and she explains: "If as late as 1984 my parents were put under some pressure to put disabled children into institutions, I wondered what must have it been like for families in the '30s.

"It was also a great excuse for me to also research the history of learning disabilities in this country and I learnt some stuff that really surprised me.

"For example, I knew that the Nazis had tested out extermination methods on people with disabilities first, but what I didn’t know was that they'd got that idea from the British and Americans. Eugenics was a popular movement in the UK and the US before World War Two.

"The other thing I discovered was that even then, between the '30s and '50s, when people with learning disabilities were being put into asylums, only ever a third of people in the UK actually got sent to the asylum.

"So I got really interested in the story of those two thirds who stayed with their families – I'd never read about them. So that got me developing this family who were loving and were trying against the odds to stay together."

Emma Claire Sweeney will be at Segrue Books of Radlett, Watling Street this Friday, (July 29), 7.30pm. Details: 0203 7933113, segruebooks.co.uk