Miriam Pollack says she will never stop hearing the screams of her two sons as they were being circumcised.

"They were quite different from any other screams these children have ever had," said the Berkeley resident and former Jewish day-school teacher. "I had them circumcised because I felt, as a Jewish mother, this was my obligation and even joy to do, to bring these children into the faith and peoplehood that I love."

But after years of reflection, Pollack has reached a different conclusion.

"How many thousands of Jewish boys and Jewish men did we lose during the Holocaust because they couldn't hide? All the oppressor had to do was pull down their pants," she said.

Pollack, whose sons are now 13 and 17, has written about her new thinking on circumcision in "Jewish Women Speak Out: Expanding the Boundaries of Psychology." The book, which is edited by Kayla Weiner and Arinna Moon, will come out this fall.

Pollack, who now runs a business diagnosing and tutoring people with learning disabilities, maintains that issues of gender and power are central to the ritual of circumcision.

"Circumcision functions to bond the baby boy to a male-defined community, a male-defined God, over and against the authority of the mother," she writes in the book.

"Our culture has totally disarmed us as women," Pollack said. "It is a cutting not only of the baby boy, but a violation of the maternal-child bond."

Circumcision, first mentioned in the Bible when Abraham is commanded to circumcise his sons, continues to be practiced by the vast majority of American Jews.

"Circumcision and being buried in a Jewish cemetery are two of the most fundamental commandments observed by even the most assimilated Jews who don't observe anything else," said Rela Geffen, a sociology professor at Gratz College in suburban Philadelphia.

"Any kind of ritual can be questioned," she said. "But this is so fundamental. Jews have been willing to die to preserve this."

Orthodox Rabbi Howard Zack takes an even stronger stand on the subject.

"Circumcision is first and foremost a biblical commandment," said Zack, spiritual leader of Oakland's Beth Jacob Congregation. "We're obligated through our relationship with God, through our entire history to follow the commandments."

For the rabbi, the opposition of Jewish parents to circumcision is as distressing as their abandonment of other principles of Judaism, including the laws of Shabbat and kashrut.

"And it's more painful because it's just one more core Jewish belief that is falling by the wayside," he said.

Though he would never tell anyone that circumcision is free of pain, Zack said, "There are a lot of things that cause pain in our lives." Those include wonderful aspects of life such as relationships. "No one guarantees us — God least of all — a life free of pain."

Nevertheless, some opponents of the ritual have become increasingly vocal, setting up organizations advocating an end to the practice that has been a central tenet of Judaism.

The Bible tells Jews not to offer blood sacrifices or to harm the body in any way, yet "circumcision is largely regarded as blood sacrifice," said Norm Cohen of Birmingham, Mich.

Cohen, a member of the National Organization to Halt the Routine Mutilation of Men, has written an alternative ceremony for a brit milah that he is offering online. One-third of NOHARMM's membership is Jewish.

Cohen, the son of a rabbi, also is concerned about the impact of circumcision on the mother-son bond.

"Circumcision is a betrayal of trust that babies have in their parents, and in their mother, particularly. Whatever happens to the baby, the baby attributes to the mother, regardless of the good intentions that are present."

In the medical establishment, the once-favorable attitude toward circumcision is also changing. The American Academy of Pediatrics has said there is no medical indication to support the surgery.

An estimated 60 percent of newborn males in the United States are circumcised today, a figure that has been dropping for about two decades from a one-time high of 90 percent. The United States is believed to be the only country in the world that routinely circumcises male babies for non-religious reasons.

Dr. Dean Edell, a Bay Area writer and media host, is a vocal opponent of circumcision. Even the authoritative Dr. Benjamin Spock is changing his tune.

As recently as 1992, "we felt there was no medical indication to perform routine circumcision on newborn boys," said Dr. Michael Rothenberg of Seattle, co-author of the last two editions of Spock's famous book on baby- and child-care.

Rothenberg, pediatrics and psychiatry professor emeritus at the University of Washington, added, however, that he and Spock understand that "there would be families who, for religious reasons, feel it is necessary to perform the ritual."

Pollack's change of heart evolved 13 years after her older son was circumcised, when he was becoming a bar mitzvah in 1991. That's when she attended an anti-circumcision symposium taking place in San Francisco.

"What I learned there confirmed every intuitive feeling I had," said Pollack, who is now a member of the San Anselmo-based anti-circumcision organization called NOCIRC.

Pollack first wrote about her opposition to the ritual in the newsletter of her former congregation, Kehilla Community Synagogue. Even in the very liberal atmosphere of a Jewish Renewal congregation, she recalls, many people were up in arms. But she remembers others coming to her quietly, thanking her for bringing up the issue.

Although she willingly speaks to individuals and groups upon request, Pollack never initiates discussions among Jews about circumcision.

"It's too complex and painful," she said about the subject. "I'm not interested in proselytizing about this."