Mother recalls learning her adopted embryo was 24 years old: "This is crazy"

The parents of a baby girl, who grew from an embryo frozen for 24 years, are calling her birth a miracle. Emma Wren Gibson was born last month to Tina and Benjamin in Knoxville, Tennessee, and researchers at the University of Tennessee say this is the longest frozen embryo to come to birth.

Last March, when she was 25 years old, Tina Gibson received an embryo that was just one year younger than her. According to the faith-based clinic's medical director, of the roughly 1,000 embryos that are transferred to new parents each year, about 15 percent are done there.

"Twenty-four hours labor but it was worth it, I'd do it again for her," Tina said.

Twenty-four might be little Emma Wren's lucky number.

Tina and her husband Ben were struggling to have kids of their own. Her father suggested she look into so-called "embryo adoption," reports CBS News correspondent Adriana Diaz. 

Couples struggling to have a child can create embryos through in vitro fertilization. Sometimes embryos are leftover, which can be frozen and donated for other couples to use -- couples like Tina and her husband who applied for one at the national embryo donation center and were accepted. 

"We were going through the profiles, it doesn't tell how long they were frozen, so we had no idea," Gibson said. "And so, the day of the transfer, ….Dr. Keenan was like 'Hey! This is going to be a world record!' And I was like, 'What? Are you kidding?'" 

Dr. Jeffery Keenan, who performed the procedure, said the couple would have had the option to not go forward when they found out the age of the embryo, but said there was no hesitation. 

"They said 'Wow! That's great, let's go!" Keenan said.

Tina remembers the moment differently. 

"I was like, 'That is not neat, that is not what I want! I was like 'I want a baby, it's probably not going to work, like this is crazy!'" Tina recounted.  

Emma's birth was 24 years in the making, but her parents say it was worth the wait.

"If this embryo would've been born when it was supposed to have been we could have been best friends!'" Tina said.

The Gibsons say Emma is a healthy baby. One expert told CBS News that the embryo's successful development is a mix of luck and science, since methods of freezing embryos weren't as good in the past as they are now.