A month later, a group of doctors in Rome reported similar results: They had implanted presumably abnormal embryos into 18 women struggling to conceive. Six became pregnant. All six bore healthy infants. The consortium now reports 24 normal births. A hospital in Spain has reported 13 healthy infants.
A year later, a study by researchers at the University of Cambridge reported an intriguing possibility: Embryos might be able to “self-correct.”
‘We as a profession have been disposing of thousands and thousands of completely normal embryos, with normal potential.’ – Norbert Gleicher
Professor Magdalena Zernicka-Goetz led the study while waiting on further test results to find out if her 12-week unborn child had abnormalities. (An early genetic test for babies in the womb suggested he did. He was born normal as well.)
The professor decided to learn more about abnormal embryos and created “mosaic” embryos using mice. The term mosaic refers to embryos showing a mixture of abnormal and normal cells. The study suggested these mosaic embryos weeded out abnormal cells during development.
And since PGS testing uses cells from the part of the embryo that forms the placenta, it’s unclear if the results are an accurate picture of the tissue that forms the unborn child.
(It’s also notable that since many IVF embryos haven’t undergone PGS testing, physicians likely have been implanting mosaic embryos for decades without knowing it. It’s impossible to know how many healthy people born through IVF would have been deemed abnormal by PGS tests.)
Gleicher estimates tens of thousands of normal embryos may have been discarded over the last two decades—including embryos belonging to women who gave up on having children because they thought a normal pregnancy was impossible.
In an email interview, Gleicher said he thinks fertility doctors are more open to rethinking the practice of implanting mosaic embryos. Last year, the ASRM released an opinion saying it could be ethically justifiable to implant abnormal embryos, though it still strongly discouraged implanting embryos with “a high likelihood” of abnormality.
Gleicher says the toughest remaining pushback comes from the PGS industry that makes millions of dollars from the tests. Estimates vary widely, but Grand View Research Inc. reported the pre-implantation genetic testing market was valued at $129 million in 2015.
Other companies have even more specific ambitions. An IVF specialist working with the startup Genomic Prediction told MIT Technology Review in November he believes the company will be able to predict which embryos might develop treatable conditions like Type 1 diabetes.
Could that lead to predicting height, weight, IQ, or social skills of embryos—a drop-down menu for choosing or eliminating babies? Physicist Stephen Hsu told Technology Review it’s entirely possible, though he thinks many would deem it unethical.
But if determining some undesirable qualities is already deemed ethical, it’s difficult to predict where the line would stop.
For Halem, who told her story to New York magazine last fall, the statistics and odds seem irrelevant when she looks at a photo of her infant daughter healthy and whole. “Here’s this little abnormal embryo, okay?” she told the reporter. “This is what they would have thrown away.”