In what's thought to be an Australian first, a woman from Brisbane has unknowingly given birth to a baby whose genetics belong to strangers.
The error was discovered in February by major fertility company Monash IVF, after the birth parents asked to transfer their remaining frozen embryos to another provider.
Monash IVF has said "human error' was the cause of the embryo mix-up.
While experts are saying this case is unprecedented in Australia, it's happened multiple times in the US, with cases hitting the headlines as early as 1999.
It's led to questions about whether stricter regulations need to be enforced here.
Birth mother the 'presumed legal parent'
Griffith Law School Associate Professor Malcolm Smith said under current legislation governing artificial inception procedures, the birthing mother was presumed to be the legal parent, as was her partner.
However, that legislation was designed for situations where a donor embryo was used, not where a mix-up occurred.
There was a possible legal argument that the valid consent that legal frameworks rely on was not given by the mother, due to the clinic's mistake and embryo mix-up, and a challenge to legal parentage may therefore be possible.
"That would ultimately have to be determined by a court," he said.
Any decision would also likely turn on what was in the best interest of the child.
A complex moral dilemma
Macquarie University Associate Professor Mianna Lotz, who specialises in reproductive ethics, said should an embryo mix-up case make it to court, bioethicists like her may be drawn upon to give evidence.
"Many ethicists want to emphasise the moral significance of the interests of the gestational/birthing mother, which can often be overlooked in favour of the interests of genetic progenitors," she said.
"We put a lot of weight on the labour and the investment of the woman."
Associate Professor Lotz said in Australia, parenthood was often defined as comprising two distinct roles, but society was rife with examples of co-parenting and mixed families, where a child may have more than two parents.
"There is more to the question morally speaking than just who gets assigned legal rights, and whether those legal rights are a right to exclude the other party entirely is something that needs to remain an open question,"
she said.
Embryo errors have occurred multiple times overseas
There are a number of documented cases of embryo mix-up in the US, where families have taken legal action as a result.
Examples include a lawsuit filed in 2021, where a mix-up at a Californian clinic saw two couples raising children that were not biologically theirs for months, before swapping the infants.
In a more recent case, a US woman from Georgia sued her clinic after giving birth to a baby of African-American appearance, despite herself and her donor being white.
Adam Wolf is the US-based lawyer representing the woman involved in that case, and has represented eight clients who have experienced an embryo mix-up — both parents whose embryos were accidentally implanted in another woman, and mothers who birthed children who were not biologically theirs.
He said any time such an error occurred it was "a tragedy for everybody involved".
"Whether you are the birth parents or the biological [parents] … this type of mistake is really the cardinal sin for a fertility clinic."
'Wild West' days of fertility industry in US
Mr Wolf said these were the "Wild West days of the fertility industry" in the US.
"There's virtually no oversight, no regulation, at least as it pertains to the American fertility industry."
He said Australia could learn from the US experience, and instigate stringent government oversight.
"You could have random and unannounced inspections of the labs of fertility clinics, there could be training and credentialling programs for the people who work in the labs of fertility clinics."
Representing both sides has left him with a profound understanding of what both biological and birth parents go through in an embryo mix-up case.
"For the biological parents, who sometimes have never even met their children, I mean, how horrific," he said.
"To think about some strangers raising your child, not being able to know what your child looks like, maybe not being raised with the same set of values or with the same faith, that you would want your child to be raised.
"Then on the other side of it, for the birth parent who wants to keep her child, this is the child that she grew, that she birthed, that she's raising, that she's sometimes breastfeeding, on taking care of, bonding with."
From his experience in the US, the genetic parents typically got custody of the child if they wanted it.
"I think the courts gravitate toward the importance of biology," he said.
The situation may play out differently in Australia.
An issue stretching back to 1999
Australian journalist Genevieve Gannon has been monitoring the issue of embryo mix-ups going all the way back to 1999, when the first widely-reported case, Fasano v Rogers, in the US, hit the headlines.
"Donna Fasano gave birth to twin boys that she and her husband Richard named Vincent and Joseph, however DNA testing later revealed that Joseph was the biological son of Deborah and Robert Rogers, who were patients at the same IVF clinic the Fasano's had attended," Ms Gannon said.
"After DNA testing proved Joseph was the biological son of Deborah and Robert, his birth-parents relinquished custody on the condition that they could have a relationship with him. Donna said at the time, 'We’re giving him up because we love him'."
Ms Gannon said it was "heartbreaking" to read about what happened to the two families.
"Unfortunately, the meetings between the Fasano's and the Rogers were tense, and the Rogers sought a court order to stop the Fasano’s from seeing Joseph."
Ms Gannon researched multiple similar cases while writing a book, The Mothers, which follows two couples who suffer the consequences of an embryo mix-up.
"There have been instances of mix-ups all over the world."
Australian IVF providers face controversy
Australian IVF companies haven't operated without controversy.
Anastasia and Lexie Gunn allege the Queensland Fertility Group used the wrong donor sperm for two children, who both have been diagnosed with serious health conditions.
In June last year, the couple were pursuing legal action against the group.
And in one of the largest settlements involving an IVF clinic, Monash IVF agreed to settle a 700-person class action lawsuit for $56 million in August.
Patients at Monash IVF alleged they were told by the company their embryos had abnormalities, which were measured by a now-suspended test.
It meant patients may have discarded viable embryos, which they allege were instead used for scientific purposes.
Earlier this year, patients of IVF clinic Genea say they were not able to get in touch with the company for days after a cybersecurity incident and data breach.
