When Michelle Timke's son was born 12 years ago, she had the baby circumcised because "that's just what you did."

Ten years later, when pregnant with her second son, Banyan, who is now 21 months, she researched the topic with her husband. They decided against it, believing circumcision is only a cosmetic surgery.

Timke expected the medical staff to frown on the decision. But instead, Timke recalled, a delivery nurse at St. Luke's Hospital in Chesterfield said she didn't understand why so many people go ahead with it.

"I feel kind of guilty that my eldest son is circumcised," Timke said. "You're doing something to your child that you can't reverse and they don't have a say in it."

Circumcision isn't the automatic procedure it used to be. In the 1960s, circumcision rates peaked at 85 percent. Now, only about half of all baby boys are circumcised, according to the Agency for Healthcare Research and Quality.

Rates vary widely by region and are lowest on the West Coast, where only one out of three baby boys gets the procedure.

In St. Louis, local hospitals report circumcision rates of 75 percent to 90 percent. But there are signs that the trend is making its way here. Doctors say parents are asking more questions about the procedure and thinking more critically about the decision.

Part of the national trend can be attributed to immigration from Latin American and Asian countries, where the procedure is less common. But there's also a growing number of parents who are deciding against it because they see it as an unnecessary or unnatural intervention.

Circumcision, or removal of the foreskin surrounding the tip of the penis, involves pulling and clamping the skin to cut off blood flow before making the incision. The procedure typically takes 10 minutes and is usually done before the baby leaves the hospital. Doctors routinely use anesthesia to reduce pain, and complications from the surgery are rare.

Some religions, including Judaism and Islam, consider circumcision a holy ritual and a connection to previous and future generations. Circumcision as a medical procedure is primarily an American custom, starting with Victorian-era beliefs about cleanliness and chastity, according to historians. The procedure became routine in hospitals in the early 1900s, and continued as the accepted practice for parents and doctors.

The medical reasons for circumcising are less clear. The American Academy of Pediatrics leaves the decision to parents and their doctors, saying the pros and cons are not significant enough to make a recommendation either way.

Complications from the procedure, including inflammation or excessive bleeding, are rare. Circumcised boys develop fewer urinary tract infections in their first year (about 1 in 1,000) compared to uncircumcised boys (1 in 100). The risk of penile cancer is reduced in circumcised men, although the overall risk of the disease remains very low.

Conflicting research doesn't give a clear answer on whether circumcision reduces the risk of sexually transmitted diseases or affects sexual sensitivity. Recent studies out of Africa suggest circumcised men are less likely to acquire HIV from an infected woman. But circumcision is not considered an effective defense against the virus.

"I tell people there's not a real medical reason for them to have a circumcision," said Dr. Jack Klein, chief of obstetrics at Missouri Baptist Medical Center, where 1,873 of the 2,144 boys born in 2007 were circumcised. "I will tell you the majority reason that people get circumcised is because they want their kid to look like other kids."

That social conformity is reason enough, say some parents concerned about future locker room comparisons and sexual relationships.

"I really didn't want to be faced with a teenage boy asking me why I didn't do this and not have a really good reason for him," St. Louis resident Amy Zimmerman said of her 2-year-old son John.

Tricia Hagan of Des Peres and her husband spent five minutes discussing the issue.

"We didn't ever really consider not doing it," she said. "Certainly as they become older and have girlfriends, it's just something to think about long-term."

Some mothers said watching a video of a circumcision was enough to turn them against it.

"I was sobbing by the end of it," said Valerie Hickman of St. Louis, whose son Benjamin is 7 months old. "I find it a bit cruel to cut my newborn child for what I feel is a cosmetic preference."

Other parents choose to leave the decision to their sons when they get older. But circumcisions on older boys and adults can be more complicated and expensive.

Ultimately, it's a personal decision, said Dr. Joseph Kahn, chief of pediatrics at St. John's Mercy Medical Center.

"Like every decision for every surgery on every child," he said, "it really needs to be something that's discussed with the parents."