There was a desperate longing in Patti Bortman's heart when her only child packed his bags and went away to college in 1997.

(OK, so he moved only one city to the south, from Kensington to neighboring Berkeley. But let's not let geography get in the way of a good drama.)

Suddenly, there was a huge empty space in Bortman's life. Something was missing, and it didn't take the 55-year-old therapist long to figure out what.

"I realized I wasn't quite done being a mom yet," Bortman said.

That's when she decided to get involved with a Jewish Big Brother Big Sister program in the East Bay.

Before she knew it, Bortman was submitting a set of her fingerprints and undergoing an extensive background check. There were intense interviews at her Kensington home and at her Walnut Creek office. And a half-day training session.

But it was all worth it. Bortman became a Big Sister to 11-year-old Adreana 20 months ago, and their relationship has blossomed ever since.

"My friends have said to me, 'What a wonderful thing you are doing,'" Bortman said. "But I get as much out of it as she does. It's really a lot of fun. I love hanging out with her."

The program matching Jewish adults with Jewish kids from ages 7 to 14 was started two years ago by Jewish Family and Children's Services of the East Bay, which is based in Berkeley.

It's a collaborative project with Big Brothers Big Sisters of the East Bay.

The premise of any Big Brothers Big Sisters program is to provide a role model, confidant, friend and mentor to a young person who needs an adult presence in his or her life.

The JFCS program adds a Jewish element to the relationship.

A lesbian couple in the East Bay, for example, didn't just want a male role model for their 10-year-old son. They also wanted this Big Brother to be Jewish.

"We are a religious home, we have our own level of observance, and we wanted someone who would have these things in common" with our son, said one of the women, who requested anonymity but did say that her family attends a Conservative synagogue.

"Also in the back of our mind was the hope that the relationship with the Big Brother would develop, and that he would end up participating in our son's bar mitzvah in three years."

However, most of their "big brother-little brother" relationship "is actually not Jewish-oriented," she added.

Likewise, Michael Eisenberg of Oakland said he and his little brother "have not done anything Jewish together, except once he and his mom came over to our house for Passover dinner."

Eisenberg, a 57-year-old business consultant, became a Big Brother because "I never had children of my own, and I'm living with a woman who has a daughter. It came up in conversation between us that this would be nice for me to do."

Not knowing about the Jewish Big Brothers program, he signed up with the regular program in the East Bay, and was then asked if he wanted to be paired with a Jewish boy through JFCS.

Now, he and his little brother, 12-year-old David, are on the cover of the JFCS' Big Brothers-Big Sisters brochure.

Eisenberg said their list of activities includes going to professional sporting events, playing sports, going fishing or crabbing, doing homework and hanging out.

While Eisenberg has become an important father figure to David, Bortman's relationship with Adreana is a little different.

Adreana already has a mother, but the only child also wanted a Big Sister as a friend and confidant. And she wanted to learn more about Judaism, she said. Before she met Bortman, the only thing Adreana knew about being Jewish was that Chanukah was a holiday similar to Christmas.

"I didn't even know I was Jewish until the third grade," Adreana said. "When I got a Big Sister, I asked for a Jewish Big Sister because I wanted to learn more about being Jewish."

Bortman has since exposed her to High Holy Days services, seders and the story of Chanukah. Together, they volunteered serving dinner to the homeless at Congregation Beth El in Berkeley.

Bortman used to belong to Beth El, but described herself as "not religious." Still, she was quite able to expose Adreana to a new world of traditions and customs. Adreana now says she'd like to celebrate a bat mitzvah.

"We also do a variety of other activities, like just hanging out at my house, or baking cookies, or taking the dog for a walk," Bortman said.

The JFCS program has so far matched 15 children with 15 adults, but has a particular need right now for male Big Brothers.

A similar program run by the S.F.-based JFCS in Marin has been up and running for seven years. It currently has more than 20 matches.