Scarcely 20 years ago, Chinese Premier Li Peng said people with intellectual disabilities shouldn't have children, because "mentally retarded people give birth to idiots."

Contrast that with two years ago, when President Hu Jintao attended the opening ceremonies of the Special Olympics world summer games in Shanghai, and 80,000 people filled the stands.

Mr. Hu's appearance was more than a symbolic turnaround. Shanghai also had set up more than 200 "sunshine homes" for job training and housing for intellectually disabled people, and the Chinese government made a commitment to build 10,000 such facilities throughout the nation, says Matthew Aaron, president of Special Olympics Pennsylvania.

The transformation in China shows how the 41-year-old sports competition for people with disabilities has also changed the attitudes and policies in countries where it has gained momentum.

"There are now more than 700,000 Special Olympics athletes in China," said Mr. Aaron, who served on the headquarters staff at the Shanghai games. "It is an example not only of explosive growth, but a change in mindset. China is a society where people with intellectual disabilities had often been shunned.

"But now there are all these residential homes, and without Special Olympics that never would have happened."

Special Olympics has been in the spotlight recently because of President Barack Obama's remarks on the Jay Leno show that his low bowling score was "like Special Olympics or something."

The president quickly apologized, and Special Olympics officials have used the resulting dustup to point out all the program's benefits, including its role in lessening discrimination throughout the world.

Gary Siperstein, a University of Massachusetts-Boston professor and longtime research expert on people with intellectual disabilities, said a new study shows that the Shanghai games had a significant effect on young people's attitudes there.

In a survey of 800 young people in three major Chinese cities, he found that their evaluation of how competent intellectually disabled people are jumped an average of 20 percent after the Shanghai games, and their willingness to interact with them climbed 15 percent.

Dr. Siperstein said he has seen this phenomenon throughout the world, and noted that those who work as volunteers at Special Olympics events "dramatically change their views of people with disabilities."

"One of the key elements," he said, "is that they recognize not only the competence of people with intellectual disabilities, but the ethic of these athletes. I remember one volunteer in Japan saying to me, 'I couldn't believe the person in that ice skating race who fell, and got up, and fell, and got up and still crossed that finish line.' It's that concept of, 'Hey, they're like I am.' "

The fresh mindset is not unique to foreign nations, he said.

In a recent analysis of several U.S. surveys, Dr. Siperstein's Center for Social Development and Education found that "as individuals become more involved in Special Olympics, from just hearing about it, to donating money to it, to actively volunteering, as the level of involvement increases, their perceptions of individuals with intellectual disabilities dramatically changes."

In particular, he said, Special Olympics volunteers are much more likely to support inclusion of intellectually disabled people in mainstream schools and jobs.

The benefits spill over to the athletes themselves.

Special Olympics athletes end up being employed at a rate that is almost twice as great as for people with intellectual disabilities generally, Dr. Siperstein said.

Mr. Aaron believes those numbers stem partly from the fact that the athletes gain self-confidence and motivation, but the program often empowers the families as well.

"Many family members may initially tend to believe what the broader society is telling them, that your son or daughter can't participate in a sport or lead a productive life or hold a job, and once they are involved in Special Olympics, their attitudes change."

All of this creates a ripple effect, and now that Special Olympics is active in more than 180 nations, Mr. Aaron believes it will have global impact.

"The social benefits can't be underestimated. Special Olympics uses sports as a platform to achieve many other benefits in the lives of our athletes."