His bar mitzvah was about to begin, but Wesley Baer was nowhere to be found.

He was located several tense minutes later, wandering down a dirt road near a playground. Two guests escorted him back, and, seemingly unaware of the potential crisis, he hugged his father, Avi.

His father smiled and shrugged. It was the day his son would become a man in the eyes of God.

But it was also a normal day.

Wesley, who has Down's syndrome, mental retardation caused by an extra 23rd chromosome in every cell of his body, had been straying off on his own a lot lately.

After he disappeared from school one recent day, a search party found him a few blocks away at a Ralphs supermarket, swinging on a bench in the garden section, eating popcorn and drinking chocolate milk.

Wesley, an affectionate 13-year-old, has shoulder-length, straight blond hair and wears glasses.

Doctors in South Africa, where he was born, told his parents that he might have a normal life, might be a contributing member to society, might learn to talk — always with an emphasis on might.

"He might never have a bar mitzvah," his mother, Jessica, told her mother.

If Wesley were going to have any chance in life, his parents quickly decided, they would have to leave their country, which was just emerging from apartheid. It was a place where the disabled could easily be lost.

The United States, they knew, had laws requiring schools to provide education and other services to the disabled.

Avi already had U.S. citizenship, thanks to his American father, and several of Jessica's relatives had settled in Southern California.

The family moved to Torrance before Wesley turned 2.

His parents divorced when he was 4, but he kept them close.

He knew something was wrong with him, but it was always other people who noticed more.

He took up karate, and he played video games. He sometimes went to synagogue with his parents, who belong to a tiny Orthodox congregation based in office space above a 7-Eleven store in Rancho Palos Verdes.

Eventually he learned to read.

By the time he was 11, a full-fledged bar mitzvah seemed possible.

The rabbi, Yitzchok Magalnic, had never worked with such a child before, but he consulted with other rabbis who had. Even the child who cannot understand cannot be excluded, Judaism teaches.

Avi accompanied Wesley to Hebrew school, held each Sunday. They stayed afterward for private lessons with the rabbi.

Bar mitzvahs are usually held on Saturdays, the Jewish Sabbath. But his parents wanted to be able to take photographs, which are outlawed on the day of rest.

And so about 100 guests arrived Sunday at the rented community center in Hesse Park in Rancho Palos Verdes.

They signed the guest book — "we are so proud of you," "you have become such a wonderful young man" — and paged through albums, which included photographs of the first time Wesley tasted ice cream, a family trip to Israel and a sonogram from when he was a 21-week ordinary-looking fetus.

Men sat on one side of the room, women on the other, as is the practice among Orthodox Jews.

Avi put a red tie on his son, who had just been found, and tucked in his shirttails.

With his father occasionally whispering to him, Wesley recited several blessings from memory, then read English transliterations of the Torah segment of the day. His mother held back tears.

"You do not know what the opposite of truth is," Avi said in a speech honoring his son. "You have no need for this word. Your whole being is one of genuineness, and anything less than that would be foreign to you."

Toward the end, he described Wesley's arrival in the world: "He came complete with 10 fingers and 10 toes and lots of other really cute bits, and in keeping with my motto — 'why be like everyone else?' — we quickly made space for his extra chromosome and off we went."

It was the first time that day that anybody mentioned his condition directly.