She delayed a hysterectomy to create embryos that later were implanted in her sister, a surrogate mom for her 2 1/2-year-old daughter, Natalie. If a uterus transplant were possible, "I would have wanted to consider it," she said. "I'm so happy that I have a child, but I kind of missed out on something."

To be transplant candidates, women must have frozen embryos so there is no fertility issue complicating the chances of success, Del Priore said.

Here is how the process might work:

People donating a loved one's organs would be asked to donate the uterus, too. In the six-month experiment with the New York Organ Donor Network, nine out of 150 families agreed and eight wombs were successfully removed.

A uterus stays viable for about 12 hours, so the recipient would need to be ready for surgery once the retrieval begins.

The transplant would be through a vertical cut about 6 inches long, from the belly button to the pubic bone. The woman would need to be stable on anti-rejection drugs for at least three months before pregnancy would be attempted.

Then, previously frozen embryos would be transferred to the new womb in the usual manner through the vagina. (Doctors do not want the woman to have vaginal sex soon after the transplant because of an added risk of infection.)

The baby would be delivered by Caesarean section to avoid other risks involving the transplanted uterus. After the birth - or two years after the transplant if no pregnancy is achieved - the uterus would be removed to minimize the risks of anti-rejection drugs to the woman.

The drugs generally are not dangerous to a fetus although certain ones should be avoided, said Dr. Vincent Armenti, kidney transplant chief at Temple University School of Medicine in Philadelphia. He keeps a registry of pregnancies in transplant recipients throughout North America.

As of mid-2005, 990 women had had 1,547 pregnancies with results not much worse than the general population. Of the 772 pregnancies in kidney recipients, 590 births resulted (the rest miscarried or chose abortion). About half of babies were born prematurely - most only slightly - and much of this was due to the mothers' high blood pressure, not the transplant.

Only six babies died within a month of birth, and 4 percent had birth defects, some of them mild and fixable with surgery.

"The consensus of the community, supported by registry data, is that pregnancy can be safe in this population," Armenti said.

But some are wary.

"I think we have to learn quite a few things" before proceeding, said Stefan Schlatt, a researcher at the University of Pittsburgh, where a failed uterus transplant recently was done in a Rhesus monkey. Scientists are preparing to try again. Others have been done in mice, rats, rabbits and pigs, with offspring only in rodents.

"The whole thing is complicated. I think it's not really ready for prime time," said Dr. James Grifo, an infertility expert at New York University, who gave Del Priore a grant for rat research years ago.

The president of Del Priore's hospital, Dr. Bruce Logan, called the research "exciting and promising," but warned: "Every step in this long research process must be handled in a measured, prudent manner. Our first concern is always the safety of our patients."

The ethics board has approved the plans with the understanding it will reconsider once a patient is chosen.

"We want them to approve the actual patient, not just the process," Stega said.

The cost is unknown but could top $500,000, including two weeks of hospitalization, Del Priore said. He expects it to be shared by the hospital, charities that support infertility research, the patient, and insurers who cover the embryo creation part.

Some outsiders question whether it's right to take a uterus unless a donor agrees before death.

"Before anybody gets to use a reproductive organ ... should the donor not have the right to control that?" asked Arthur Caplan, bioethics chief at the University of Pennsylvania. "It's got symbolic importance that's far different from a pancreas or a liver."

Dr. Christine Cook, an infertility specialist and chief of women's health at the University of Louisville in Kentucky, where hand transplants were pioneered a decade ago, said donation and consent issues can be handled effectively.

"The complexity we've introduced into parenting requires a lot of thought," but uterus transplants hold "exciting" potential to help many women, she said.

R. Alta Charo, a bioethicist at the University of Wisconsin, questioned whether such major surgery and the risk of anti-rejection drugs is justified.

"That's a pretty high price to pay in order to be able to give birth to a child" when other options like adoption and surrogacy exist, she said.

Veronica Pena would risk it.

The 36-year-old Chicago woman's uterus was damaged during the birth of her daughter 15 years ago and had to be removed. She and her husband want more children.

"We've tried adoption but it's unfortunately very expensive and is not as easy as it sounds," and pregnancy attempts with a surrogate failed, she said.

Last week, she called Del Priore, asking about a transplant.

1

2