Scientists have created synthetic human embryos from stem cells without using eggs or sperm in a development that raises challenging moral and legal questions.
The research has not been peer-reviewed and is yet to be published, Zernicka-Goetz said at the event.
“I just wish to stress that they are not human embryos,” Zernicka-Goetz said to CNN. “They are embryo models, but they are very exciting because they are very looking similar to human embryos and very important path towards discovery of why so many pregnancies fail, as the majority of the pregnancies fail around the time of the development at which we build these embryo-like structures.”
The synthetic human embryos were grown from single human embryonic stem cells that were made to develop into three distinct tissue layers. At present, the synthetic model embryos are restricted to test tubes.
According to Zernicka-Goetz, her research is not aimed at creating life but at preventing the loss of life. She and her team had earlier created model embryos from mouse stem cells that had shown the initial states of a brain and heart.
Moral, Legal Implications
When it comes to human embryo research, most nations follow the 14-day rule, which limits an embryo created through the fertilization of an egg to be grown only for 14 days.However, synthetic embryos like those developed by Zernicka-Goetz and her team using stem cells are not legally embryos and thus not bound by these same rules, which raises questions about their legality.
“On the other hand, the closer stem-cell-derived models of human embryos mirror human embryos, the more important it is to have clear regulations and guidelines for how they are used.”
He stressed the need to proceed “cautiously, carefully and transparently” in the field so as to avoid any “chilling effect” among the public.
From Synthetic Embryos to Grown Animals
While experiments with synthetic embryos are ongoing, the question of whether they can grow up into living creatures still remains.Synthetic embryos of mice that Zernicka-Goetz and her team earlier created were implanted into female mice wombs but failed to develop into grown creatures.
Similarly, researchers from China have experimented with implanting synthetic embryos created from monkey cells into the wombs of female monkeys. This, too, had failed.
“Given how rapidly the field has been moving over the last few years … I’ve become more and more concerned about how close we are to generating a complete human embryo model with the potential to develop into a viable human embryo or fetus. This is not some far-fetched, remote possibility,” he said.