HYANNIS, Massachusetts (Reuters) - Eunice Kennedy Shriver, who emerged from a powerful male-dominated political family to found the Special Olympics and become a leading advocate of the mentally disabled, died on Tuesday at the age of 88.
Shriver, the sister of former President John F. Kennedy, died about 2 a.m./0600 GMT at Cape Cod Hospital in Hyannis, the Massachusetts town on Cape Cod synonymous with the Kennedy dynasty.
"Her work transformed the lives of hundreds of millions of people across the globe and they in turn are her living legacy," her family said in a statement.
U.S. President Barack Obama praised Shriver's Special Olympics work and called her "an extraordinary woman who, as much as anyone, taught our nation -- and our world -- that no physical or mental barrier can restrain the power of the human spirit."
In March, Obama apologized for comparing his bowling skills to those of Special Olympics participants during an appearance on "The Tonight Show" television program.
Shriver was married to Sargent Shriver, whose long public service included starting the Peace Corps under President Kennedy. Sargent, 93, a former vice presidential candidate, suffers from Alzheimer's disease.
She was born July 10, 1921, the middle child of the nine children of Joseph P. Kennedy Sr. and his wife, Rose.
As a child, she wanted to compete athletically against her brothers, including John, elected president in 1960 and assassinated in 1963; Robert, a New York senator whose presidential bid ended with his assassination in 1968; and Edward, who has served as a senator from Massachusetts for more than 45 years.
Edward Kennedy, who is battling brain cancer, said in a statement that even as a child his sister had a "boundless passion to make a difference."
"Though the Special Olympics will be her enduring monument, in our family she'll be remembered as a loyal and loving sister, a treasured wife to Sarge, and a wonderful mother and grandmother," he said.
Shriver was always a part of her Democratic brothers' political campaigns but her advocacy work crossed party lines.
Republican President Ronald Reagan praised her "enormous conviction and unrelenting effort ... on behalf of America's least powerful people" in 1984 when he awarded her the Presidential Medal of Freedom, the nation's highest civilian honor.
Well into her 80s, Shriver still was seen in the halls of the U.S. Capitol seeking support for her cause.
She started the Special Olympics Games in 1968 to foster fitness and self-esteem for the mentally handicapped. Her concern was attributed to her relationship with older sister Rosemary, who was said to have been mildly retarded and spent much of her life in long-time care after a lobotomy.
"I had enormous affection for Rosie," Shriver said in a radio interview in 2007. "If I never met Rosemary, never known anything about handicapped children, how would I have ever found out? Because nobody accepted them anyplace."
The genesis for the Special Olympics was the summer camps that Shriver put on herself for mentally handicapped children at her family's Maryland estate. Forty years after the first U.S. Special Olympics, the games have grown to include 190 nations.
Beyond an athletic competition, the Special Olympics became a public service organization that advocated research, rights and better care for its constituents. Shriver's son Timothy became the organization's chairman.
Her other children are Maria, a former TV journalist who married California Governor Arnold Schwarzenegger; Bobby, a lawyer and philanthropist; Mark, a former Maryland state legislator now in charity work; and Anthony, who also founded a group to help the mentally handicapped.
Word of Shriver's death spread quickly through Hyannis, where locals have seen the Kennedys come and go from their summer homes for decades, often in the wake of tragedy.
"The women are all very strong and it gives a lot of other women strength by watching them," Neco Rogers, whose son is a patient at the hospital where Shriver died, said in the parking lot of hospital.
Shriver was a debutante who was presented at the Court of St. James while her father Joseph Kennedy was U.S. ambassador to Britain. Early in her professional life, she worked for the State Department and then with female prisoners in West Virginia.
Shriver campaigned with her husband when he was the vice presidential candidate with George McGovern in 1972 and when he made a failed bid for the Democratic nomination for president in 1976.
Additional reporting by Matt Bigg; Writing by Bill Trott; Editing by John O'Callaghan