Advocates sought to change this perception by showing the positive aspects of their families' lives and working for full social and educational inclusion. They believed that, as with other minority groups, integration would lead to greater understanding and acceptance.
A recent study in the UK, conducted by the Down's Syndrome Association, indicates that this approach has been effective in changing public views:
The number of babies in England and Wales being born with Down's syndrome has risen to a higher level than in 1989 when serum pre-natal screening was widely introduced - with two births a day according to the latest figures.
And in an attempt to understand why more women are opting to go ahead with their pregnancies the Down's Syndrome Association has consulted parent members. The results, released in a Radio 4 documentary, "Born with Down's Syndrome," show that many believe the quality of life for people with Down's syndrome will be better than in the past and that those with Down's syndrome are more accepted in society.
Following the introduction of screening for Down's syndrome in 1989, the number of babies born with the condition steadily fell from 717 to just 594 at the start of this decade.
Since 2000 the birth rate has increased, reaching 749 births of children with Down's syndrome by 2006, the latest year for which figures are available.
The study suggests that when differences and disabilities are simply seen as part of everyday life, people are less likely to have negative expectations or to make decisions based on fear. Some of the parents mentioned that they knew a person with Down's syndrome or another disability and that this had influenced their views.
I expect a similar improvement in public attitudes toward autism as we achieve greater integration in schools and workplaces. There's more discussion of this study at the Left Brain/Right Brain blog.