Another step in "an explosion of new techniques and ideas for studying early development" of human embryos came last week from Israel. Researchers there have successfully grown mouse embryos for 12 days, which is about half the animal's natural gestation period.
The rough equivalent for a human would be a first-trimestre baby. They published an article in Nature last week .
The news was crowded out by another big announcement about human embryos: that separate research teams have created artificial embryo-like structures. Both pose threats to human dignity, but of the two, the Israeli research may be more dangerous.
It seems that ectogenesis is coming closer - the Brave New World vision of hatcheries where artificially conceived babies are gestated in gigantic vats.
The lead author, Jacob Hanna, of the Weizmann Institute of Science, was interviewed about his work in MIT Technology Review . He acknowledges that there are ethical issues.
"I do understand the difficulties. I understand. You are entering the domain of abortions," says Hanna. However, he says that researchers are already experimenting on and destroying surplus embryos from IVF clinics. Using the same logic, ectogenesis is not really a big deal.
At the moment, there's effectively a global ban, amongst reputable scientists, to stop investigating embryos at the 14th day of development. But many bioethicists and researchers want to extend this to some unspecified time span. Hanna is one of them. "I would advocate growing it until day 40 and then disposing of it," Hanna says. "Instead of getting tissue from abortions, let's take a blastocyst and grow it."
At the moment, the mouse embryos only develop if they have been attached to the uterus wall, at least briefly. But Hanna says that his team would like to grow the embryo entirely in vitro.
And if the 14-day limit is scrapped, he looks forward to doing similar research on human embryos.
"Once the guidelines are updated, I can apply, and it will be approved. It's a very important experiment," says Hanna. "We need to see human embryos gastrulate and form organs and start perturbing it. The benefit of growing human embryos to week three, week four, week five is invaluable. I think those experiments should at least be considered. If we can get to an advanced human embryo, we can learn so much."
Eventually it might even be possible to grow embryos for their organs, according to William Hurlbut, a doctor and bioethicist at Stanford University. "I don't think that organ harvesting is so far-fetched. It could eventually get there. But it's very fraught, because one person's boundary is not another person's boundary."
And in the other big development last week, as mentioned above, four lab groups almost simultaneously published research showing that it is possible to create structures which are nearly identical to human embryos.
According to Nature, "Two teams published their results in Nature on 17 March; last week, two other groups reported similar results on the bioRxiv preprint server that have not been peer reviewed. These experiments offer a window into a crucial time in human development, and an opportunity to better understand pregnancy loss and infertility without experimenting on human embryos."
Most of what scientists know about the early development comes from studying human embryos up to 14 days - the legal limit in most countries. The research groups have created structures they call blastoids or iBlastoids which could bypass the need for stopping research at 14 days.
Two of the scientists involved in an Australia-based study explain in The Conversation that: "While iBlastoids and blastoids both seem to be structurally and functionally similar to real blastocysts, it is not yet clear exactly how closely they resemble true embryos formed by a sperm and an egg. While the models were shown to share gene patterns and respond in culture in ways characteristic of actual embryos, researchers also saw significant anomalies, such as unsynchronised growth and cells that are not usually present in an embryo."
"I'm sure it makes anyone who is morally serious nervous when people start creating structures in a petri dish that are this close to being early human beings," Daniel Sulmasy, a bioethicist at Georgetown University, told NPR . "They're not quite there yet, and so that's good. But the more they press the envelope, the more nervous I think anybody would get that people are trying to sort of create human beings in a test tube."
These developments, linked to pressures from bioethicists to scrap the 14-day rule, suggest that a Second Great Stem Cell War is just over the horizon. The first began when scientists demanded around 2001 that they be allowed to experiment on human embryos but it subsided after 2007 with the discovery of induced pluripotent stem cells. At the time, it seemed impossible to grow embryos in labs beyond 14 days. Now that it looks feasible, there will be another push to grow embryos in Petri dishes up to a new limit.
To invoke Aldous Huxley's prescient 1932 science fiction novel Brave New World is the oldest, biggest and stalest cliché in bioethics. But, when confronted with this news and with this ethical indifference, imagination fails me.
Folks, we're heading towards Brave New World.