Studying for seven months to become a bar or bat mitzvah would be a big commitment for any busy adult. In the case of Richard Bender what's most amazing is that until last month, he wasn't even Jewish.

Bender formally converted to Judaism only three weeks before he and five other adults became b'nai mitzvah on May 24 at San Francisco's Congregation Sherith Israel. The group was the last to go through the ritual under Cantor Martin Feldman, who initiated the adult program more than 20 years ago and retired last month after 43 years at the synagogue.

"It was amazing. There wasn't a dry eye in the house," Shelley Gottlieb, Bender's wife, said of the ceremony. "It was much more meaningful than a child's bar mitzvah because for a child it's a rite of passage; they almost get pushed into doing it. For these people, it was a choice."

Adults who decide to become b'nai mitzvah make the decision for a wide variety of reasons: the frustration of not being able to read Hebrew or chant the liturgy during High Holy Day services, a desire to rediscover their religious roots or to accomplish what they could not in childhood.

"It's a tremendous accomplishment," said Feldman, who noted that most of his adult students don't know the Hebrew alphabet when they begin their studies, but end up chanting from the Torah and conducting the entire service seven months later. "It's a very big commitment," Feldman said of the weekly Monday night classes and hours of studying.

For Bender, the journey to becoming a Jew and a bar mitzvah had many stops along the way. "My father was very anti-religious, and my mother was sort of a spiritual seeker who dragged me as a child to every Christian denomination and spiritual movement," he said. As an adult, Bender married a Roman Catholic and then a strict Presbyterian. "So religion has always been part of my life, but I've never felt any faith."

It wasn't until he met Gottlieb that he was exposed to anything Jewish. "To my surprise, I found myself very interested in Judaism," said Bender. "The more I learned, the more I wanted to learn."

The 41-year-old San Francisco resident enrolled in Feldman's b'nai mitzvah class last fall only to learn basic Hebrew so he could follow along in prayer services. But when the class moved from Hebrew vocabulary to preparing for the b'nai mitzvah ceremony, he found himself hooked.

"I guess I had one of those spiritual epiphany moments when I realized I wasn't done," said Bender. "I felt at home spiritually and was ready to convert."

Of all of Feldman's students who became b'nai mitzvah May 24, it was Rebekah Alessi, who gave birth just 12 days before her bat mitzvah, who faced perhaps the biggest challenge. With her baby overdue and the doctor insisting on a Cesarean section, Alessi persevered and succeeded in delivering baby Shoshana on Mother's Day, May 11.

"It was ultimately very challenging," said Alessi, 47, of San Francisco. "I never could have imagined I could pull it off in 1,000 years. It has been profound on every possible level."

Like many women her age, as a child Alessi watched her brothers become bar mitzvah as teenagers but missed out on a similar experience because of her gender. When she grew older, she found herself drawn to religion, practicing Buddhism and occasionally attending Catholic Mass with her husband. But it was at her mother's Jewish burial last year that Judaism beckoned to her — in the chanting of Feldman.

"Immediately after I fell back into the tradition and loved it," she said.

Many adults who do not learn Hebrew as children find themselves standing helplessly on the sidelines as their children prepare for their special day. That was how Jan Maisel and Connie Tabas say they felt as their children studied for their b'nai mitzvah over the past two years.

Previously, "it never seemed in the past that Hebrew would add anything to my life as an observant Jew," said Maisel, 53, of Tiburon, who was the oldest of five children and the only one who did not have a bat mitzvah. Like others in the group, Maisel said she found time in her busy life as a pediatrician and a mother to attend Feldman's classes because she knew the cantor would be retiring this year.

"I am utterly delighted I can read the prayer book now," she said, adding that her bat mitzvah has deepened her involvement in Jewish-related volunteer work.