Both have taken place within Northern Ireland, the part of the UK with the highest incidence of the condition, chiefly because both Catholic and Protestant communities there have a tradition of large families which means that the number of babies born to older women - the high risk category for Down's - is much greater. All this has also produced a culture which has fostered notable advances in the treatment of the syndrome.In one of the two studies, Dr Norman Nevin, Professor of Genetics at Belfast City Hospital, has tracked every baby born with Down's Syndrome in the province in the past 25 years to determine the changing pattern of the disorder. In the other, Dr Chris Conliffe of the Institute for Counselling and Personal Development, has surveyed the entire Down's population in the province - the first time a total survey has been done anywhere in the UK.He discovered that the incidence is a lot higher than was previously thought, and that people with Down's are surviving much longer than was supposed - he even came across a woman aged 77 with the condition But Northern Ireland is special in another way. Over the past two decades, a group of activist parents have established a network of support groups under the umbrella of the Northern Ireland Down's Syndrome Association which has profoundly altered the lives of children with the condition. And it has led them to achieve far more than the experts had thought possible.Norman, and the group of other young adults on the dry ski-slope in Belfast last week, were the pinnacle of that achievement.

(They were practising for a parent-free skiing holiday in France next weekend.) He and others have recently completed their Duke of Edinburgh gold award, which involved four days unaccompanied orienteering and survival in a German forest. At home, many now in their twenties have found jobs and are preparing to leave home for semi-independent housing schemes. One has passed a driving test and drives her own car.It is all a long way from how people with Down's Syndrome have been viewed in the past. The condition was first identified in 1866 by Dr John Langdon Down, a supporter of the eugenics movement which saw mental and physical handicaps as a manifestation of degeneracy - a philosophy which led eventually to the entire Down's Syndrome population of Germany being experimented on and exterminated in the Nazi Holocaust. And if more modern reactions were less extreme, there was until as recently as 20 years ago a routine recommendation in this country that such children be placed for life in an institution.A number of factors have changed that. Central to them, according to Dr Conliffe, has been the insistence by families that they will look after their Down's children at home.

This has not just provided the children with more intensive stimulation. It has also created a network of vocal advocates who continually challenge the medical and education systems.Thirty years ago, half of Down's children died before the age of five; today, thanks to advances in surgery on the heart and bowel disorders which affect them, 80 per cent survive to 30 and beyond, and most have a life expectancy of over 50. At home, early physiotherapy and speech therapy has been evolved. In education, Down's children have been discovered to have better visual than auditory skills and their IQ can virtually double when measured this way. As a result, their traditional special schools have been augmented, thanks to parental pressure, by the option of integrating them into mainstream schools.Despite all this, the stereotypes are slow to change. "I've always tried to educate the general public but I don't think I'm winning," sighed Elizabeth Doherty as she watched her son, Kieran, 23, follow Norman down the dry ski-slope. "Their looks are a barrier they find hard to get over," she said.Kieran has an NVQ in Retailing and has just had a job interview on the open job market.

But perhaps the most interesting finding of this month's reports are the unexplained clusters of babies born with Down's in particular areas at particular times. "I'm becoming more and more convinced that external factors might play a part," said Professor Nevin. "Down's Syndrome is caused by an additional chromosome and we know that the chances of this increase with the mother's age But there could also be an environmental influence. We have looked at a number of things - diet, drugs, chemicals. There could well be some other factor which acts on the eggs of old mothers and triggers it off."The Post Office has now provided him with post-code computer software to plot his 25 years of figures on a map. "We will look for things like whether there is clustering around land-fill sites, for example," he said.