When Tina Gibson got married seven years ago, the 26-year-old knew it was unlikely that she would have children naturally. Her husband, 33-year-old Benjamin Gibson, had cystic fibrosis, a condition that can make men infertile, the couple told CNN.

The East Tennessee pair decided they would eventually adopt a child instead - and that they would foster several children in the meantime, until they were ready.

Then, last year, during a break between foster children, her father told them about something he'd heard on the news - embryo adoption, according to CNN. Gibson couldn't get the idea out of her head.

She submitted an application for the adoption in August 2016, and by spring had three embryos from the same anonymous donor transferred into her uterus.

It was only when she was preparing for the transfer that a doctor and lab director explained the embryos Gibson had chosen could lead to a "world record," she told CNN.

On Nov. 25, Gibson gave birth to a healthy baby girl, Emma Wren Gibson.

"People say, 'oh it's science,' but no I think it's a gift from the Lord. It's a gift from the Lord, for sure," Tina Gibson told NBC local affiliate WBIR.

The National Embryo Donation Center in Knoxville, Tennessee - the embryo adoption program that helped Gibson get pregnant - said Emma holds the record for the longest-frozen embryo to come to birth, citing research staff at the University of Tennessee Preston Medical Library in Knoxville.

The embryo was frozen 14 October 1992, when Gibson was about 18 months old, and was thawed on 13 March 2017, by embryology lab director Carol Sommerfelt, making it 24 years old, NEDC officials said in a news release posted to Standard Newswire Tuesday.

Surprised by the age of the thawed embryos, Gibson said in March, "Do you realise I'm only 25? This embryo and I could have been best friends," according to CNN.

But some experts say it's unclear whether Emma's birth is, in fact, a record.

Zaher Merhi, director of IVF research and development at New Hope Fertility Center in New York, told CNN that American companies are not required to report the age of the embryos they transfer to the government - just the outcome of the pregnancies.

"Nobody has these records," he said.

Some experts say the previous record was set in 2011, when a woman in New York gave birth to a healthy boy born from a frozen embryo created 20 years earlier.

Sommerfelt, who transferred the embryos into Gibson's uterus, said she was amazed that embryos of such an old age could result in the successful birth of a baby.

"It is deeply moving and highly rewarding to see that embryos frozen 24.5 years ago using the old, early cryopreservation techniques of slow freezing .. can result in 100 percent survival of the embryos," Sommerfelt said in the release.

About 12 percent of American women 15 to 55 - or 7.3 million - have used some sort of fertility service, according to the Centers for Disease Control and Prevention.

The use of assisted reproductive technologies doubled in the past decade, and in 2015 the procedures resulted in the births of 73,000 babies - about 1.6 percent of all U.S. births.

The NEDC in Knoxville is a faith-based organisation founded in 2003 that receives embryos from all 50 states, according to its website.

About 75 percent of the donated embryos survive the freezing and thawing process, and about 49 percent of transfers result in a live birth, the website says.

A live baby count on its website shows that 686 babies have been born as of Tuesday.

"We say that our reason for existence is to protect the sanctity and dignity of the human embryo," marketing and development director Mark Mellinger told CNN. "We are big advocates of embryo donation and embryo adoption."

While Gibson said she was amazed by the age of the embryo, she told CNN she "just wanted a baby."

"I don't care if it's a world record or not," she said.

"Emma is such a sweet miracle," Benjamin Gibson said. "I think she looks pretty perfect to have been frozen all those years ago."

2017 © The Washington Post

This article was originally published by The Washington Post.