The number of American women giving birth by Caesarean section has reached an all-time high, with nearly one-quarter of babies now being delivered through the surgical procedure, according to government statistics being released this week.

Continuing a steady retreat from the "natural childbirth" trend, the Caesarean section rate jumped 7 percent in 2001, reaching 24.4 percent of all live births -- the highest rate since the government started collecting the statistics in 1989.

The reasons for the rise, and the issue of whether it's good or bad for women and their babies, are the subject of an intense debate that has been raging at medical conferences, in medical journals, in doctors' offices and at birthing centers. It's an unusually emotional debate, especially when it comes to women who want a "C-section" for their first baby -- even when labor poses no obvious danger.

The phenomenon also illustrates the complex ways in which the practice of medicine evolves, and how non-medical issues such as costs, social customs and sexual politics influence decisions about care.

"I think there is rationality on both sides of the debate," said Judith Walzer Leavitt, a professor of medical history and women's studies at the University of Wisconsin Medical School. "But there's also some things that . . . we might look on as less scientific -- like training and experience, like religious beliefs and mind-sets, like political issues of the day."

Christina Neumeyer, 39, a family and marriage therapist from Carlsbad, Calif., agonized over whether to get a Caesarean for her son's birth two years ago. A strong believer in holistic medicine, Neumeyer had tried for years to get pregnant. But then, knowing she came "from a long line of women who have had excruciating, dangerous vaginal births," she was terrified of what might happen to her or her baby during delivery.

"My mother had a 48-hour labor when any reasonable doctor would have done a C-section, and she's required multiple surgeries since then to repair damage," Neumeyer said. "I had a grandmother who almost died in labor three times, and an aunt who had a similar experience."

So after long talks with her doctor and husband, a lot of soul-searching, and convincing her insurance company she was too "fragile" to risk labor, Neumeyer scheduled a Caesarean. "I had waited a long time to get pregnant and wanted some sense of control," she said.

Some experts see the surging Caesarean rate as a welcome development. Medical authorities in the 1980s and 1990s had launched a campaign to reduce the number of C-sections. Doctors particularly targeted the practice of routinely performing Caesareans on any woman who had had one before. Repeat Caesareans were derided as often unnecessary, and as subjecting women to costly and potentially dangerous surgery and a long recovery.

But before long, problems began to emerge.

"Fetuses died. Mothers died. Mothers' uteruses ruptured. As the reports of these disasters started to appear in the medical literature, obstetricians became much more cautious," said Michael F. Greene, director of maternal and fetal medicine at Massachusetts General Hospital in Boston.

By 1996, the Caesarean rate started creeping back up. Last year, the percentage of women who had a vaginal delivery after a previous C-section plummeted 20 percent, dropping to an all-time low of 16.5 percent, according to preliminary data from the National Center for Health Statistics. The final numbers, being released on Wednesday, are not expected to vary significantly.

For obstetricians, one factor may be that malpractice insurance rates have begun skyrocketing again. That has made them even more skittish about labor, particularly for women who have already had a C-section. In fact, women who would like to try a vaginal birth after a previous Caesarean increasingly find that their doctors or hospitals refuse.

But it is not just the number of repeat Caesareans that is increasing. More and more women have been getting C-sections for their first baby. That rate climbed 5 percent in 2001, up to 16.9 percent of all live births, the new data show.

Part of the reason is that more women are having babies at older ages, when they tend to have more complications, and more multiple pregnancies linked to fertility treatments. At the same time, the nation's obesity epidemic means that more overweight mothers are carrying more big babies, which are more difficult to deliver.

Perhaps the most controversial factor is the number of women who are choosing Caesareans even though there may be no perceptible danger to their health or their baby's. Although this practice remains relatively unusual, opponents and proponents of the trend say it appears to be increasing.

"I have women coming into my office who want a primary C-section for whatever reason -- they have anxiety about fetal distress or anxiety about how it's going to change their bodies. They don't want vaginal tears and are just preferring a scheduled C-section," said Michele Gerber of Pacific Coast Women's Health in Encinitas, Calif., who delivered Neumeyer's healthy baby boy, August, two years ago.

Although some women may seek Caesarean sections simply for convenience, perhaps the biggest motivation is growing concern about the effects of labor and delivery on their bodies. Specifically, concern has been increasing about "pelvic floor" disorders -- ills that result when muscles, ligaments and other tissues become damaged during labor and childbirth. That can cause problems later in life, most notably urinary and fecal incontinence and other complications that can occur when organs shift out of place.

"It's a big problem," said Linda Brubaker, director of female pelvic medicine and reconstructive surgery at Loyola University Medical Center in Chicago. "Twenty to 30 percent of women become incontinent after a single vaginal delivery. One out of 20 have an anal sphincter rupture, which can cause bowel incontinence."

Many women also complain about a change, or even a deadening, of sexual sensation because of nerve and tissue damage.

Gerber opted for C-sections herself after going through labor with her first child. "It's often women in the medical profession. OB/GYNs see the bad outcomes and see the women down the line who have had vaginal deliveries and have problems."

But she said it is still largely unfashionable for women to choose a C-section the first time. "There's a lot of pressure to have this beautiful experience, and sometimes it's unrealistic. It can have a negative effect on women. It was a natural thing for women to die in labor. It's very politically incorrect to talk like that. I just feel like women deserve a choice."

All the same, many women's health advocates have long viewed Caesareans as epitomizing the male-dominated, overly medicalized birth process, said Andrea E. Tone, director of graduate studies in the school of history, technology and society at Georgia Institute of Technology in Atlanta. Some opponents of C-sections accuse obstetricians of favoring surgical deliveries because they can be scheduled at the doctors' convenience and earn bigger fees.

"Many feminists pointed out rightly, I think, that statistically more C-sections were being done than were absolutely necessary. C-sections kind of symbolized the power of the medical procedure," she said.

Tone had her first child by Caesarean, on Election Day 2000, even though she was desperate to avoid one. "I remember crying, 'C-section and George Bush on the same day!' In my mind a C-section was an evil to be avoided. I remember thinking I'm going to be so embarrassed to tell my feminist friends."

Still, more women are opting for C-sections, and more doctors appear willing to do them. "It is not any more a taboo subject," said Marco Pelosi II, an obstetrician-gynecologist in Bayonne, N.J. "I can actually foresee that in the next five years that Caesarean section by request will no longer be associated with a stigma."

Pelosi noted that in many other countries, particularly in South America, Caesareans are the norm.

Others, however, argue that it remains far from clear that vaginal delivery does increase the risk for pelvic floor disorders. And Caesareans are much more expensive, potentially dangerous, and lead to a far more difficult recovery than vaginal deliveries.

"The risks of surgery definitely outweigh the risks of pelvic floor dysfunction," said Laura Riley of Massachusetts General Hospital in Boston, chair of the committee on obstetric practice of the American College of Obstetricians and Gynecologists. "People have been having vaginal deliveries for a gazillion years, and the babies are fine."

Bruce Flamm of the University of California at Irvine medical school cites a study that found nuns fairly commonly experience pelvic floor problems. "How can it be true that having a baby is the main culprit when a large study comes out showing that a large number of nuns who have never had a pregnancy or a baby have urinary incontinence?"

The debate over Caesareans is unlikely to die down any time soon. Meanwhile, Neumeyer, the California woman who decided to have a Caesarean, agrees that women should have the option. "There is this idea floating around that women like to schedule their C-section between their manicures and their pedicures. I think most women take it more seriously."

Christina Neumeyer wheels 2-year-old son August at their Carlsbad, Calif., home. She chose to have a Caesarean section because of "the excruciating, dangerous vaginal births" women in her family have had.