Patrizio said storage fees at his clinic cost $600 a year, but can cost twice as much, depending upon the clinic.

“The problem is, even if an embryo is considered abandoned, even if there’s a contract in place, it’s very difficult to get rid of. What if one day someone shows up and says, ‘Where’s my embryo?’ And you wind up on the front page of the newspaper for destroying someone’s embryo? The damage would be done,” he said.

For that reason, Patrizio said, his clinic doesn’t destroy abandoned embryos.

Richard Vaughn, a founding partner of the International Fertility Law Group, a national law firm that specializes in fertility matters, with offices in New York and Los Angeles, said he knows of no fertility clinics willing to dispose of abandoned embryos.

“They don’t want to be responsible for a wrongful death,” he said.

The embryos typically don’t require much room.

“Frozen embryos take up very little space,” Dr. Sherman Silber, director of the Infertility Center of St. Louis, said. “You could put a whole city in a lab.”

But while the embryos are small, the liquid nitrogen tanks in which they’re housed aren’t. Patrizio noted a number of clinics are running out of room for the tanks and are outsourcing storage of abandoned embryos to companies like Reprotech, a national storage firm he calls “a mini-storage facility for embryos.”

“Many clinics don’t want to have the abandoned embryos in their facility for liability reasons,” Patrizio said.

Patrizio and Sweet said the issue of abandoned embryos is sometimes discussed at global fertility conferences, but generally remains within the industry what Sweet calls “the elephant in the room,” that’s neither publicly discussed nor addressed.

The problem, Allen said, is that clinics are fertilizing too many eggs.

The number of eggs a woman can produce in a monthly cycle leading up to an egg retrieval varies, depending upon her age, ovarian reserve, medical history and response to fertility drugs.

During the 1990s, many clinics deemed it necessary to inseminate as many of a patient’s eggs as possible, because many embryos didn’t make it through the freezing and thawing process. Now, Allen said, techniques have improved.

“With the technology we have, creating a large amount of surplus embryos is completely unnecessary,” Allen said, noting embryologists now know only a few eggs at a time need to be inseminated.

“[But] you still see many physicians with the mentality of, ‘the more, the merrier.’ So you see [some women] having 40, 50 or 60 eggs retrieved in a cycle and the embryologist gets the orders from her doctor to inseminate all of them — and the question isn’t asked if the patient even wants that many inseminated.

“Nobody’s going to have 30 kids,” she said.

Allen said regulation is needed within the fertility industry and is hopeful the U.S. will follow examples established by Germany and Italy, where only a few embryos can legally be created and transferred at a time, thus avoiding surplus embryos.

Sara Raber, 43, said she knew frozen embryos were part of the process when she began IVF treatments in 2008.

After several rounds, Raber and her husband had two sons in 2010 and 2012 in New York.

Both boys were conceived through the transfer of fresh embryos into Raber’s uterus at the Center for Human Reproduction (CHR), a New York fertility clinic. Other embryos were frozen during her treatments. Raber said she had the option of using frozen embryos when she began trying for her second child, but opted to use new eggs instead.

“I knew I wanted to save the frozen embryos for a rainy day,” Raber explained. “They were my insurance policy.”

Raber said she tried to use one frozen embryo to have a third child in 2014, but suffered a painful miscarriage. That’s when she struggled with the decision of what to do with her five remaining embryos.

“Even though I knew I was done procreating, it was very hard to make the final decision,” Raber said. “For months, I sat on the paperwork.”

The clinic gave Raber four choices: She could continue to pay storage fees for her frozen embryos, donate them to another woman, authorize the clinic to destroy them, or give them to the lab for research purposes.

Ultimately, Raber donated her embryos to her fertility clinic’s lab for research purposes.

“I didn’t want to donate them to a stranger,” Raber explained. “I felt like if I donated the embryos to a stranger, it would be our child out there that we weren’t raising.”

Raber said she understands why many patients quietly abandon their embryos.

“They had their babies. They’re focused on child care now. And the storage fees are a financial strain they don’t want to endure.”

Some embryos, though not technically abandoned, are stuck in legal limbo, which happens when the couple who created the embryos can’t agree on what to do with them.

That was the case with the actress Sofia Vergara. The “Modern Family” star created two embryos with her former partner, Nick Loeb. When the couple broke up, Loeb wanted custody while Vergara wanted to make certain the embryos were never implanted. Today, the embryos remain frozen, as Vergara and Loeb continue to battle in court.

According to Vaughn of the International Fertility Law Group, there have been at least 13 cases similar to Vergara’s that have reached appellate courts. He predicts there will be more lawsuits in the future.

“It will continue to be a growing issue until we have a clearer way of dealing with embryo legislation,” Vaughn said, noting there are no national laws in place that address abandoned embryos.

Tad Pacholczyk, director of education at the National Catholic Bioethics Center, agrees a national debate over frozen embryos will spill into future generations.

Pacholczyk said he knows of cases in which couples, unable to agree on what to do with surplus embryos, continue to pay storage bills — and intend to do so for the rest of their lives.

When the couple dies, a new generation will be left to grapple with the embryos.

Pacholczyk advises couples to create trust funds for surplus embryos, so that storage fees can be paid indefinitely.

“Creating a trust fund for the frozen embryo shows a couple is taking responsibility for what they created,” Pacholczyk said. “To me, the complexity of the situation about what to do with these excess embryos is a powerful reminder that when you cross moral lines, there’s a price to be paid.”

The medical community is uncertain how long frozen embryos remain viable.

Silber of the Infertility Center of St. Louis said if the embryos are properly frozen, they could remain viable for decades.

“We have reason to believe embryos frozen using modern technology can last over 100 years,” Silber said.

Even when patients indicate they want to donate their embryos to science, Sweet said, there are limited facilities willing to take them.

We have reason to believe embryos frozen using modern technology can last over 100 years. Dr. Sherman Silber

“We have 18 percent of our patients telling us they want to donate their embryos to science, but I can’t find anyone to take them,” he said, noting the University of Michigan is among the few places in the nation that have accepted abandoned embryos in recent years. “Now I need to go back to those patients and find out what they want to do, but we often can’t find these people.”

Concerned about the growing population of abandoned embryos, Sweet established Embryo Donation International in 2011 in Fort Myers. The program has gathered surplus embryos from 67 fertility clinics, all from women and couples who have explicitly granted permission to donate their embryos to infertile patients.

Sweet said Embryo Donation International has provided a means for patients to donate embryos to women and couples eager to have a baby. But the program can't make use of embryos abandoned by patients who fail to sign the paperwork.

Those embryos, Sweet said, remain stuck.

In an effort to curb the creation of more embryos that might end up in limbo, Sweet made the decision a decade ago to make his fertility clinic a “non-discard” facility, meaning all of his patients must sign paperwork indicating they will not discard their embryos.

Sweet said he made the decision for ethical, not religious, reasons.

“The embryos were abandoned by the patient, and I felt if I abandoned them they were abandoned a second time."

Sweet knows there is much his profession needs to tackle when it comes to abandoned embryos. The process, he said, will not be easy.

Still, he said, it’s time for the industry that’s been all about making babies to finally address the embryos that were created, then abandoned, in the process.

“I think many of us realize that we have a bit of a mess and I’m not sure doctors know how to fix it,” Sweet said. “But we need to try.”