Delivery-room doctors in Detroit didn't expect Sidney Simon to survive when he came into the world three months early on March 26, 1917, weighing only 1.5 pounds. He has exceeded all expectations, and then some: The longtime Palo Alto resident will celebrate his 100th birthday on Sunday.

"When somebody asks me how did I manage to get to be so old, I tell them, 'Because I didn't die. If you don't die, you get older,'" he joked Wednesday while sorting through birthday cards at his Eichler home after his morning water-aerobics workout at the YMCA.

One hundred is just another number to a man who has defied the odds throughout a life that has spanned two World Wars, Prohibition and the Great Depression and witnessed today's tech boom. He once beat a Hall of Fame tennis player at doubles; developed a barnacle-resistant patented paint that allowed Navy ships to stay at sea longer during World War II; and taught himself how to play the recorder to help pass time while recovering from a debilitating car accident that left him bedridden. (He ultimately joined the Midpeninsula Recorder Orchestra, where he's still a member 50-plus years later.)

"Yeah, I've done a lot of things in my little life; it took me 100 years to get this far," he said.

After Simon's rocky start, his family moved to Los Angeles when he was 2. Simon discovered his lifelong passion for tennis when somebody gave him a racket, and he played pickup games at the public park.

He became good enough to compete in various city and high school tournaments, which led to one of his most-talked about matches: a doubles match where he and his partner defeated Bobby Riggs at the tennis club where they all were members in North Hollywood.

"We were both about 15 years old. I remember Bobby had just come back from Kalamazoo where he had won the National 15 and Under and was starting his career."

The defeat was quite an upset at the time.

Simon continued to play in tournaments until he tore his rotator cuff during a match when he was 86, which ended his time on the court.

Simon's proudest accomplishment, however, was his 55-year marriage to pianist and Stanford University music professor Naomi Sparrow, whom he met at a Young People's Socialist League gathering in Berkeley in 1943 and married two weeks later.

He had graduated from University of California, Berkeley, and was working as a chemist at the Mare Island Navy Base. She was about to leave for Chicago for three months to teach music.

"I met her ... and that was the beginning. We looked at each other and said, 'Let's get married' and went to the Justice of the Peace. She left (for Chicago) two days later," said Simon, who referred to her as his bride from that day on until her death in 1998.

"We never had an argument in our whole life. You know why? She was always right. There was nothing to argue about. She was so wonderful. I was a very lucky guy."

The duo came to Palo Alto in 1954 when Simon took a job as paint chemist at Benjamin Moore. Two years later, Simon said they got lucky and found their "forever home" in a new Joseph Eichler-developed tract for $26,500.

Simon later persuaded Eichler to build the Eichler Swim & Tennis Club on Louis Road, where Simon has been a member for more than 40 years.

Simon credits his longevity to the raw onion he eats daily but acknowledges that it could be related to his many years of healthy living and his circle of friends.

"You need friends and activities when you get older," he said. "Relationships keep you alive."

One of Simon's three grandchildren, Joshua Miller, said people seem to flock to Simon.

"He has a sharp wit and is always in a good mood," Miller said. "He's pretty special. I walk around and see how he connects with other people. ... I feel like I can learn a lot from him."

It shouldn't be surprising to learn that Simon plans to celebrate his birthday with a series of parties over the course of three days with his family and "only" 50 or so of his closest friends.

"Being old isn't so bad," said Simon.