Groups supporting people with Down's syndrome on Thursday called on the European Court of Human Rights not to recognise the right to tests that would detect the condition before birth.
The Strasbourg-based court must "recognise the human condition and protect the right to life of people with Down's syndrome and those handicapped", said the 30 associations from 16 countries.
The groups were meeting as the court was examining the case of a Latvian mother, Anita Kruzmane, whose 10-year-old daughter suffers from the chromosomal disorder.
Before Latvian courts she had accused her doctors of having failed to offer the prenatal screening, saying it would have allowed her to have an abortion.
After judges rejected her suit, Kruzmane took her case to the European rights court arguing that her right to a proper family life had been violated.
But the head of the international federation of Down's syndrome organisations, Ireland's Patrick Clarke, questioned whether abortions because of a genetic defect should be a right.
To eradicate a disease is one thing, but to eradicate people with a medical condition is something else, said Clarke who has an adult son with the condition.
For Jean-Marie Le Mene, the head of a French foundation that backs research into Down's syndrome, also known as trisomy 21, the Kruzmane case is part of a larger context in which parents' liberty to keep a trisomic child is "threatened by a policy of eugenics", which aims to improve the genetic composition of a population.
This policy which paths the way to almost systematic screening leads to abortions in almost all cases in which the foetus is found to be trisomic, said Le Mene.
"This is not about questioning screening or abortions but about a situation in which abortions are carried out without asking questions," he said. "We must fight these prejudices that turn a trisomic person into a calamity."
The court was expected to rule within the next few months.