In an exciting breakthrough, scientists have announced the creation of synthetic human embryos using stem cells. Prof. Magdalena Żernicka-Goetz, a professor of biology and biological engineering from the University of Cambridge and the California Institute of Technology gave a plenary address on Wednesday at the annual meeting of the International Society for Stem Cell Research, held in Boston.
“We can create human embryo-like models by the reprogramming of [embryonic stem] cells,” she told the gathered scientists.
She explained that in her lab, single human embryonic stem cells were coaxed to develop into three distinct tissue layers, a point known as gastrulation, that would typically go on to develop a yolk sac, a placenta, and the embryo itself.
“Our human model is the first three-lineage human embryo model that specifies amnion and germ cells, precursor cells of egg and sperm,” Żernicka-Goetz told the Guardian ahead of her speech at the conference. “It’s beautiful and created entirely from embryonic stem cells.”
If she has indeed achieved this, it would be the world’s first synthetic human embryo-like structures from stem cells, bypassing the need for eggs and sperm. These cells represent the very earliest stages of human development. At this stage of development, they don’t have a beating heart or a brain.
The professor told CNN that the embryo-like structures her lab created are the first to have germ cells that would go on to develop into eggs and sperm.
“I just wish to stress that they are not human embryos,” Zernicka-Goetz said. “They are embryo models, but they are very exciting because they are very looking similar to human embryos and very important path towards the 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.”
Indeed, scientists know little about the early stages of fertilization and embryonic development, leading scientists to pursue this type of research.
“We know remarkably little about this step in human development, but it is a time where many pregnancies are lost, especially in an IVF setting,” Roger Sturmey, senior research fellow in maternal and fetal health at the University of Manchester in the UK, said in a statement.
“Currently, we can say that these ‘synthetic embryos’ share a number of features with blastocysts, but it is important to recognize that the way that synthetic embryos are formed is different to what happens when a normal embryo forms a blastocyst,” he said. “There is much work to be done to determine the similarities and differences between synthetic embryos and embryos that form from the union of an egg and a sperm.”
While the development has the potential to help scientists understand genetic diseases or the causes of miscarriages, it raises serious questions about this type of experimentation and challenges existing laws. Many countries, including the US, don’t have laws that completely govern the creation or treatment of synthetic embryos. Unlike human embryos arising from in vitro fertilization, where there is an established legal framework, there are currently no clear regulations governing stem cell-derived models of human embryos.
Researchers in the US are currently limited by the “14-day rule” which limits research on human embryos to a maximum period of 14 days after their creation or to the equivalent stage of development that is normally attributed to a 14‐day‐old embryo. It is illegal to implant an experimental human embryo in a womb. In biological terms, the 15th day of embryo development is the point when the primitive streak forms: that is, the beginning of gastrulation when three layers of germ cells differentiate.
Research with stem cells from mice and monkeys has shown that even when scientists have attempted to implant them in animal wombs, they don’t survive. It is believed that researchers haven’t been able to fully replicate the conditions of pregnancy. The current research in the United States and the UK has demonstrated that it is possible to culture embryos to the equivalent of 13 days and potentially longer raising the possibility of extending the 14-day rule.
Last year, Prof. Żernicka-Goetz and a rival group of researchers at the Weizmann Institute in Israel showed that stem cells from mice could be encouraged to self-assemble into early embryo-like structures called embryoids that had an intestinal tract, the beginnings of a brain, and beating heart. The team built a mechanical womb that enabled natural mouse embryos to grow outside the uterus for more than a week, nearly half the gestation time for a mouse.
Rabbi Moshe Avraham Halperin of the Machon Mada’i Technology Al Pi Halacha (the Institute for Science and Technology According to Jewish Law), emphasized that
“Scientists can rearrange but they cannot create something from nothing, as God did in Genesis,” Rabbi Halperin said. “Scientists are merely combining and manipulating existing material. We know that actual Creation is forbidden by the Bible. And the Bible states that in any case, it is impossible for men to create a new life as only God has that ability. Even the greatest atheists have been unable to refute this.”
The rabbi told a joke that illustrated the point:
A group of scientists approached God and said that mankind had no use for Him anymore as they had created life. God acknowledged that if this was true, then Man had truly become independent. But he requested a demonstration. The scientists mixed some mud with water and began to process it.
“Just a moment,” God said. “Bring your own mud and water. I made these.”
Rabbi Halperin pointed out that the research had additional theological issues.
“What the scientists are doing is not creation,” Rabbi Halperin explained. “They are manipulating cells that God created.”
“Science is discovering wonderful cures and aids but not everything is permitted in every case,” the rabbi warned. “Certain combinations, mixing species, for example, are forbidden. Science is always exploring what Man is capable of accomplishing. The Torah shows us what is good and even worthy to do.”
“If scientists ever do develop the ability to create life, Torah law explicitly prohibits this,” he said. “But that would require creating a being that can think and speak. Life is not enough to classify a being as a Man.The rabbi explained that such a creature, alive but without independent thought or the ability to communicate, would be classified as a golem; an animated, anthropomorphic being in Jewish folklore, which is entirely created from inanimate matter, usually clay or mud.