Complaints poured in from those who said Katie Wright's remarks were denigrating.

So, in early June, Bob and Suzanne Wright repudiated their daughter on the charity's Web site. "Katie Wright is not a spokesperson" for the organization, the Wrights said in a brusque statement. Her "personal views differ from ours." The Wrights also apologized to "valued volunteers" who had been disparaged. Told by friends how cold the rebuke sounded, Suzanne Wright belatedly added a line saying, "Katie is our daughter, and we love her very much."

Katie Wright called the statement a "character assassination." She said she has not spoken to her father since. She continues to spend time with her mother but said they have not discussed the situation.

"I totally respect if her feelings were hurt," Suzanne Wright said. "But a lot of feelings were hurt. A lot."

Now other autism families who hoped to put their differences aside are shouting at each other in cyberspace. "Our struggle is not and should not be against each other," said Ilene Lainer, the mother of an autistic child and the executive director of the New York Center for Autism.

The "big tent" approach of Autism Speaks appealed to Mel Karmazin, chief executive of Sirius Radio and an early board member and contributor. "If you look at what projects Autism Speaks has funded, we are agnostic."

Karmazin, who also has an autistic grandson, added, "I never wanted to look my grandson in the eye and tell him I'm taking just one viewpoint or that I think it had to be genetic."

Bob and Suzanne Wright are sympathetic to Katie's plight, having witnessed Christian's sudden regression and his many physical ailments, mostly gastrointestinal, which afflict many autistic children.

The boy did not respond to behavioral therapies, the Wrights said, leading to their daughter's desperate search for anything that might help.

"When you have that sense of hopelessness, and don't see results, you do things that other people think is too risky," Bob Wright said. "The doctors say, 'Wait for the science.' But you don't have time to wait for the science."

The Wrights agreed to disagree with most of Katie Wright's views. But her public attack on other parents crossed a line, Bob and Suzanne Wright said in separate telephone interviews.

"I know my daughter feels deeply that not enough is being done," Bob Wright said. "The larger issue is we want to be helpful to everyone, and to do that we need information, data, facts."

Some in the traditional scientific community worry that Autism Speaks has let Katie Wright's experience shape its agenda. She scoffs at the notion.