Embryos float in a petri dish held by Dr. David Diaz. A clinic can dispose of them if five years have passed without contact with the couple. But few, if any, doctors actually do, says Dr. Richard J. Paulson, chief of reproductive endocrinology and infertility at the University of Southern California Keck School of Medicine.

Los Angles Times MARK BOSTER

Six years of frustration and heartbreak. That’s how Gina Rathan recalls her efforts to get pregnant.

Finally, she and her husband, Cheddi, conceived a daughter, now 3, through in vitro fertilization. About a year later, she became pregnant with a second child, naturally. Their family was complete.

Then, a year ago, the Fountain Valley, Calif., couple received a bill reminding them that their infertility journey wasn’t quite over. They owed $750 to preserve three frozen embryos they’d created but hadn’t used.

“I don’t see them as not being life yet,” says Gina Rathan, 42, a pharmaceutical sales representative. “I thought, ‘How can I discard them when I have a beautiful child from that IVF cycle?’ ”

Many other former infertility patients also appear to be grappling over the fate of embryos they have no plans to use: An estimated 500,000 embryos are in cryopreservation in the United States.

As with the Rathans, this unexpected conundrum often arises well after the infertility crisis has passed, triggering impassioned and highly personal debates about the science and ethics of human life. The discussion boils down to a fundamental question: What is this icy clump of cells smaller than a grain of sand?

Across the country, people with less personal stakes in the matter are also asking that question.

Colorado voters defeated on Election Day an amendment to the state’s constitution to assert that an embryo is a person. Indiana lawmakers have proposed legislation that would allow abandoned embryos to be adopted for implantation by another couple. New Jersey legislators have moved to allow unused embryos to become wards of the state. And Georgia and West Virginia are considering legislation that would give embryos “personhood” status.

Although these proposals are sponsored in large part by abortion opponents, infertility patients nationwide — whose feelings about abortion run the gamut — are finding themselves ensnared in a debate about when life begins.

“They are in the middle of this ideological war, although they may not be aware they are in the middle of a war,” says Renee Whitley, co-chairwoman of the national advocacy committee for Resolve, an organization supporting people with infertility. “This is the politics of embryos.”

Couples with leftover frozen embryos have three choices: discard them, donate to research or donate to another couple for pregnancy. The default option is to leave the embryos in a vat of minus-310-degree liquid nitrogen, paying for the storage and deferring the decision.

Embryo-protection legislation could ultimately winnow those options and, say doctors and consumer advocates for the infertile, possibly limit future infertility treatments.

“This is taking a pretty private decision and placing it squarely in the public’s eye,” says Nanette Elster, director of the Health Law Institute at DePaul University in Chicago.

Freezing excess embryos is a common strategy for in vitro fertilization. To make embryos, a doctor injects a woman with potent hormones to produce eggs. These are then harvested in a surgical procedure. The eggs are mixed with sperm in the laboratory, and some of the developing embryos are transferred into the uterus. A single cycle with fresh embryos costs more than $15,000, often not covered by insurance.

Subsequent attempts at pregnancy are less costly if frozen embryos are on hand, and the supply of extras spares a woman another round of harsh drugs to produce eggs. About half the people who undergo in vitro fertilization end up with one or more frozen embryos.

But no one can predict how many embryos will be produced and used. And as the success of the treatment has improved over the last two decades, doctors are now transferring fewer embryos to avoid multiple births.

Meanwhile, the glut of stored embryos grows and more families find themselves in a position some liken to playing God.

“They are wrestling with how to think of embryos. A person? Nothing? Something in between?” says Dawn Davenport, an adoption researcher who has an online radio show and a Web site called Creating a Family.

Infertility clinics report that they lose contact with about 15 percent to 25 percent of families with frozen embryos. According to the American Society for Reproductive Medicine’s guidelines, a clinic can consider embryos abandoned and dispose of them if five years have passed without contact with the couple and if significant efforts have been made to reach the couple. But few doctors dispose of the embryos, says Dr. Richard J. Paulson, chief of reproductive endocrinology and infertility at the University of Southern California Keck School of Medicine.

“To my knowledge, no one in the United States has ever done that,” he says. “We’re all paranoid that a couple will show up the next day and say they want their embryos.”

The federal government supports, via funding, only one option: adoption to another couple for pregnancy. In a highly publicized event at the White House in May 2005, President Bush posed for pictures with children born from adopted embryos — sometimes called “snowflake adoptions,” referring to the fact that the embryos are frozen and unique. And the Department of Health and Human Services funded a three-day conference in May to promote this alternative.

About 1,000 babies have been born in the U.S. from embryo adoption since it became available 10 years ago, said Ron Stoddart, who founded the Snowflakes Embryo Adoption Program, based in Fullerton, Calif.

However, research by Anne Drapkin Lyerly, an associate professor of obstetrics and gynecology at Duke University, as well as other surveys, have found that most families prefer not to donate embryos for adoption. In a paper published last year, of 1,020 couples with frozen embryos, 22 percent said they were somewhat or very likely to donate to another couple. Slightly more said they would probably thaw and discard them. Almost half said they would donate them to science, including for use in stem cell research.

Human embryos are the primary source of stem cells, and the uptick in stem cell research has fostered a growing demand for donated embryos. Although such research destroys the embryos, the broader effort is aimed at curing disease. This goal resonates with couples who have endured reproductive health problems, says Lee Rubin Collins, co-chairwoman of Resolve’s national advocacy committee. “Reproductive medicine is about creating life, not ending it,” she says.

Infertility patients may support embryo use in research, but much of the nation appears to be more conflicted.

No federal funding is available for embryonic stem cell research, and only eight states fund such research within their borders. Last year, Bush vetoed a bill that would have allowed federal funding for new stem cell lines derived from fertility clinic embryos.

In a survey of 1,003 adults in the U.S. published in the spring issue of the New Atlantis, about half the respondents said destroying embryos is unethical because they’re humans, but 41 percent — some of the very same people — said it was ethical to destroy human embryos in the course of research if the research can help people.

“People are not quite sure where this set of issues belongs,” says Yuval Levin, bioethics director for the Ethics and Public Policy Center, an ecumenical think tank in Washington that publishes the New Atlantis. “To some it’s an element of the abortion debate. For other people it has to do with science and medicine. We’ve never really thought through what the moral status of the embryo is.”

As for the Rathans, over the course of several weeks, the couple ruled out discarding the embryos. They discussed donating them to research but heard that option was a logistical nightmare. They pondered giving the embryos to another infertile couple.

“Before I became pregnant, I thought the decision would be easier for me,” Gina Rathan says. “But when it actually happened, I realized these are three potential lives.”

Finally, the couple paid for three more years of cryopreservation.

“I think about the embryos every day,” Rathan says. “I am their mother. I see them as my own children. They are the DNA from my husband and I. It’s something I worry about, especially when the three years is over and I have to make a decision again.”