When Frances Browner, then 21, announced she was joining the Women’s Army Corps (WAC) during World War II, her mother and most of the rest of her family were appalled. They thought that this wasn’t something a Jewish girl should do.

“She said I was trying to kill her,” Browner, now 92, said. “I can still see my mother’s face as we left on the train. She was really upset.”

More than 350,000 young women like Browner served in the armed forces during that war, in the WACs, the Navy’s WAVES, the Coast Guard SPARS, the Marines, the Women Airforce Service Pilots and as nurses. My Aunt Ruth joined the WAVES, much to the shock of her parents and her older sister, my mother.

Each had their reasons for volunteering. My aunt, no doubt, wanted to contribute to a war effort that enveloped the country, as well as to find adventure. Frances Browner’s reasons were much the same. “I wanted to get away from home,” she said. “Also, I was very upset because I’m Jewish, and Hitler was taking over all those countries.”

Of those many women, few had Browner’s wartime experience — working with scientists in secret in Los Alamos, N.M., making the first nuclear bomb.

Hers is a fascinating story of a girl from Fairfax High School with, as yet, no college education, doing mathematical calculations for some of the world’s great scientists. I heard about her from Nancy Volpert, public policy director for Jewish Family Service of Los Angeles, which provides volunteers to visit older people, like Browner. I was drawn in immediately because of my affection for my late aunt. I felt meeting Browner would be a rare opportunity to recall the wartime exploits of a generation fast slipping away. And I thought she would shed some light on the struggles of ambitious, intelligent young Jewish women in an era when they were expected to follow the traditional path of marriage, kids and homemaking.

Browner and I talked in the living room of her home in Mar Vista. She and her husband moved into the house just after it was completed as part of a large subdivision, and she raised two children there. She sat in a comfortable chair, friendly and eager to tell her story. “As a youngster, I had two wishes in my life,” she said. “One was to have a father. My parents divorced when I was 2.” The second was to go to college. But, she said, her mother “wanted me to get a job and support her. I am surprised that I actually resisted.

“I had, I think, the only Jewish mother in the history of civilization who didn’t want her kid to go to college,” Browner said.

Browner’s mother forced her to pass up a scholarship to Los Angeles City College, but she attended half time and worked part time. UCLA, her real choice, seemed too distant a goal. Then war broke out. “When the Army came along, I told my mother I’m not doing this for me or you. It’s for the world. It may sound corny, but I felt that way.”

During basic training at Fort Des Moines, in Iowa, she scored so high on her intelligence test that she was given a mysterious assignment and sent there — by train, and then by truck. “They put us in closed Army trucks,” she said. “No one knew where we were going.”

In fact, she was headed to the Los Alamos National Laboratory in New Mexico, where scientists, under the direction of J. Robert Oppenheimer, were working on the top-secret Manhattan Project, making the atomic bomb.

Browner helped with mathematical calculations, adding up long lists of figures. “After I was there a short while, I had an idea that it was some form of explosive, but I had no idea it was an atomic bomb,” she said.

She remembers Oppenheimer at work, seated at his desk smoking a pipe. Once, an uncle, passing through Albuquerque, wrote to ask her to meet him at the railroad station. “I had to go to Oppenheimer and ask for permission,” she said. “He said, ‘No, sorry, we can’t let you.’ ”

With great pleasure, she recalled how “every afternoon they had tea, and I would sit with the … scientists. Here I was a young kid who had never been away from home, and I was always interested in college and learning and having none of that in my environment, and then I get to go to a place where every day I have tea at 3 o’clock with some of the most brilliant scientists in the world.”

At night, she stored her work in a basement vault, where a testing machine was operating. After six months, she developed respiratory troubles, which eventually led to her discharge for disability. Respiratory ailments dogged her for years afterward, and, looking back, she thinks it might have been from radiation. The GI Bill permitted her to attend UCLA after the war. With her poor health, it took her seven years to graduate.

We had talked for almost an hour, and it was time for me to go. Browner had another appointment at 4 p.m.

I thought of how tough those days were for women of Browner’s generation. When she spoke of her mother, she still seemed mad, just as she was still proud when she remembered her acceptance by the scientists.

She insisted on getting up from her chair and, with the assistance of a walker, she escorted me to the front door. I looked at a photograph of her in a WAC uniform on the wall, amid family pictures. She looked pretty, friendly, smart and ready to go to war against the nation’s World War II enemies — and against the limitations that a backward time had placed on women like her.

Bill Boyarsky is a columnist for the Jewish Journal, Truthdig and L.A. Observed, and the author of “Inventing L.A.: The Chandlers and Their Times” (Angel City Press).