After a mixup at an IVF clinic, two California couples gave birth to andraised another couple’s child— a situation experts say is incredibly rare.

In this week’sexclusive cover story, Alexander and Daphna Cardinale open up to PEOPLE about the ordeal, which began shortly after Daphna gave birth to the couple’s second child in September 2019 — a daughter who, much to their surprise, looked nothing like them.That November, an at-home DNA test kit confirmed their child was genetically unrelated to either of them — and the following month, they found out that another couple at the clinic (who do not wish to be publicly identified) had delivered a child via IVF who also bore no biological relationship to the parents.

Soon, DNA confirmed the mixup, and the couples made the difficult decision to legally agree to swap children.

“This is extraordinarily rare,” IVF expertDr. Michael Alper, Medical Director, and Reproductive Endocrinologist at Boston IVF, who was not involved in the case, tells PEOPLE in this week’s issue. “When I hear of disasters like this, it really eats at my heart because I feel so bad for all those that were involved.”

Alexander and Daphna Cardinale; the couple on the cover of PEOPLE.

12/6/21 cover

IVF clinics generally double check everything to make sure a major mistake never happens, experts say.

“There’s really numerous safeguards that are put in place to keep the human error to an absolute minimum,” says Alper, an Associate Clinical Professor in the Department of Obstetrics, Gynecology and Reproductive Biology at Harvard Medical School.

Alper studied 181,800 cases looking for mistakes from small ones— like misspellings and typos— to extreme errors such as mixing up eggs, sperm or embryos.

His research found no extreme errors and 99.96 percent of the procedures had no small errors either.

“The vast majority of procedures are extremely safe in an IVF laboratory,” Alper says. “When somebody asks me, ‘Can you 100% guarantee there’ll never be an error?’ Nobody can say that for certain. But what you can say is, ‘We have a lot of systems in place to make that very unlikely.’ "

For more on the Cardinales' ordeal, pick up the latest issue of PEOPLE, on newsstands Friday, or subscribehere.

Clinics generally have their own “very precise protocols” to ensure that “nothing is mixed up,” according to Dr. Nicole Noyes, a fertility-preservation and IVF specialist at Northwell Health in New York City.

Alexander Cardinale and Daphna Cardinale with daughter.yuri hasegawa

cardinale family

“There’s lots of different ways to keep things straight,” Noyes says.

Her clinics make use of a “spotter,” a technician whose job is to check, match and positively identify samples.

Another safeguard is to use color-coded labels for vials and lab dishes, because research shows that people remember color more than they remember names.

“That has been pretty fail safe,” she says. “I’ve been doing this 30 years, I’ve been involved in about 30,000 IVF cycles and I haven’t seen a mix up yet.”

Alexander and Daphna Cardinale.Yuri Hasegawa

cardinale family

“Clearly this program did not have a fail-safe protocol in place,” says Noyes. “They obviously swapped the two samples at some point. And that’s really scary.”

Another source of concern, in Noyes’s view, is that there was a secondary lab involved.

“It sounds like there was some lack of clarity on who was actually responsible for the embryology care,” she adds. “We don’t have any secondary anything. Everything’s right here. We know what’s going on. And importantly, the patient knows what’s going on.”

source: people.com