A new mother about to check out of the hospital discovered her baby son had not been circumcised.

"I was frantic," she says. "I had visions of my son being a misfit."

To her -- and, it appears, to the overwhelming majority of new parents in the United States -- circumcision "is as much a part of the delivery process as the birth."

Though statistics are not easy to come by, obstetricians and pediatricians estimate that currently about 70 to 85 percent of newborn males undergo the genitial surgery.

There is, nevertheless, the opinion among many childbirth specialists that the operation in most cases is not necessary, despite its widespread use.

The American Academy of Pediatrics reviewed the issue in 1971 and again in 1975 and concluded, "There are no valid medical indications for circumcision" of newborn males. The American College of Obstetrics and Gynecology -- the doctors who perform the surgery -- says its position "is consistent" with that of the pediatricians.

"Definitely not necessary," says Dr. Joseph V. Collea, chief of maternal and fetal medicine at the Columbia Hospital for Women and Georgetown University associate professor of obstetrics and gynecolocgy.

He points out that circumcision -- as with any operation -- carries "surgical risk," though the "incidence of injury is very rare." Possibilities, he says, are hemorrhaging, injury to the shaft, or even loss of the penis.

One University of Washington study indicated a major complication in 1 out of 500 circumcisions.

And -- because no anesthesia is administered during the five-minute process -- Collea believes it can be painful to the baby. "Yes, I think it is. Even a newborn baby has feeling."

Babies cry during the procedure, he says, but that may be as much because they are strapped down in an uncomfortable position as from actual surgery.

Collea says he advises parents whose child he is delivering that circumcision, which costs about $50 to $100, "does not good -- and it may do harm."

The decision to circumcise or not, he says, is up to the parents. Despite his advice, "About 70 percent still request it. They say, 'Be careful.'"

Increasingly, organizations counseling parents on childbirth procedures -- including so-called "natural" birth -- inform them that they have to option not to have a son circumcised.

"We tell them there's no medical indication for circumcision," says Janet Epstein of Maternity Center Associates of Bethesda, one such counseling group. "It's their personal decision."

The United States appears to be one of the few countries in the world performing routine circumcision.

Psychologist Karen Erickson Paige of the University of California at Davis, who studies circumcision practices for a forthcoming book, "Politics and Reproductive Ritual," found that in most of the rest world circumcision was either never accepted or is rapidly being discontinued.

Outside the United States, it survives, she wrote in an article for Human Nature magazine, "where it has a religious or cultural tradition: Israel, Arab nations, some tribes in sub-Saharan Africa."

For Jews here and abroad, says Rabbi Joseph Weinberg of the Washington Hebrew Congragation, "It is tradition dating back to the Bible." In Genesis, Chapter 17, God tells Abraham, "This is my convent . . . Every man child among you shall be circumcised . . . And the uncircumcised man child whose flesh of his forskin is not circumcised, that soul shall be cut off from his people; he hath broken my convent."

God instructed Abraham that it was to be performed when a boy is 8 days old. By custom, many Jews therefore have their sons circumcised on the eighth day, usually at a family ceremony in the home call a Brit (or Bris ). It is generally done by a mohel , who is trained in Jewish tradition and licensed to perform the operation.

The Brit , says Weinberg, "is a very important aspect of Jewish family life."

Among non-Jews in this country, says Paige, circumcision "became prevalent in the '40s" when larger numbers of women started having births in the hospital instead of at home. "It started with the middle-class who were the first ones to go down to the hospital, and then filtered down."

Through the years, reasons for surgical removal of the foreskin have varied.

At one point in our past, says Paige, circumcision was thought to control masturbation, which -- it was the believed -- could lead to "masterbation insanity."

In more recent years, medical theoriests have argued that circumcision reduces the chances for cancer of the prostate for the male and of the cervix for women. The American Academy of Pediatrics, however, says there is no evidence to substaniate these assertions.

The academy does say there is evidence that circumcision can prevent cancer of the penis, but that good hygiene "confers as much, or nearly as much, protection."

The question of hygiene is one the parents should consider before making a decision. Some doctors suggest new mothers may be uncomfortable or hesitant about the cleaning process, or about instructing their son to do it himself as he grows up.

For the uncircumcised male, says the academy, "lifelong penile hygiene" is necessary. Though the risk is considered "slight," poor hygiene can result in balantis, a painful infection of the foreskin that occurs only in uncircumcised males. In some cases, an adult circumcision may be performed to correct the problem.

But says Dr. Collea, today's "normal standard of hygiene" is all that is required to prevent infection. "As long as you keep clean, you don't need to be circumcised."

Dr. Benjamin Spock, in the 1976 edition of his famous "Baby and Child Care," considers the question of hygiene "the main justification for circumcision," but, he concludes, "it is not a compelling reason" to have the operation performed.

There is some dispute as to just what proper penile hygiene entails.

"Keeping clean -- that came as a surprise to me," says a spokeswoman for Parent and Child, a childbirth education group here, who is the mother of a 6-year-old uncircumcised boy. "How are you supposed to keep it clean? I told my husband, 'That's your part of the anatomy.'"

Some experts advocate pulling back of the foreskin carefully -- but not too far -- while the baby is being bathed. Others suggest the bath alone is sufficient. Leaving the penis alone, says Spock, "is the simplest way and the one used throughout a great part of the world."

The Parent and Child spokeswoman said that when her son grew out of diapers, she told him, "When you take your bath, you're supposed to clean yourself." It was much the same thing as telling him, "You've got to clean your ears."

Why, if medical experts say circumcision is not necessary, are most parents still having it done to their sons?

Psychologist Paige thinks that part of the reason is that the word hasn't yet gotten out to most parents that they can say no to the operation.

One mother says she feared her son would be "teased" in school athletic classes if he were the only uncircumcised boy in the shower room.

Fathers who are circumcised, generally the case these days, appear to want the same for their sons.

Collea suggests, from his reading of psychological studies, that there may be some "positive psycological effect," if the boy can identify with his father, either as both circumcised, or not.

Most often the circumcision is performed on the boy's second day of life, says Collea, after it is determined he is in good health. It should not be done "if there is a questionable deformity of the genitial area," the baby is ill or was extremely premature."

At Columbia Hospital, the baby is "strapped on a table top that conforms to the baby's back so he can't wiggle." The penis is then inserted in a steel Comco clamp, shaped something like a small stapler, which holds the organ in place.

"Putting the clamp on and tightening it, that can be painful," says Collea.

"Once it's in place," though, the baby may "fall asleep."

Paige says studies are under way to detemine if there are many adverse psychological effects on newborn males from the pain of circumcision.

The incision is made with a scalpel. Normally, says Collea, "There is no bleeding. You can't even see a pink or red area. It looks perfectly natural."

Afterwards, says Collea, "We apply Vaseline or gauze to the area to prevent the diaper rubbing. If the baby wets, there may be tenderness from the urine, like any sore that gets wet." After 24 to 48 hours, the operation should need no other special care.

Whatever parents decide, physicians and childbirth educators advise them to raise the question of circumcision with their doctor before the baby is born. At the time of birth, they may not be in the right frame of mind to properly consider the choice.

If parents are afraid their son might some day regret they didn't have him circumcised, they can take consolation from this story told by a Washington mother, who one day got a call from her son, by then a junior in college.

"Mom," he told her, after hurrying to the phone from the gymnasium shower room, "the guys say I'm not circumcised."

Her reply?

"You mean you never noticed?"