Perhaps the biggest question rests on how these embryonic-like stem-cell-derived structures come to be. For some scientists, this is a catch-22 situation. Many believe that if the embryos look like embryos, research with them should be limited by the way we handle work on human embryos.
But if they’re not good enough as embryos, there’s no point in using them for research, says Chuva de Sousa-Lope. “It’s hard to understand how close they are or how different they are these days,” she says.
Scientists tend to look at the size and shape of the structures, and the genes their cells express, to determine how similar they are to typical embryos. But there are other important aspects to consider.
“First we need to agree on what an embryo is,” says Naomi Morris, a developmental biologist at the Crick Institute in London. “Is it just something that comes from the union of sperm and egg? Is it related to the types of cells they contain? [shape] Structure?”
Maybe it has to do with the capacity of the structure. A human embryo can go on to form a person. Human blasts cannot evolve into humans. Christmas.
As technology advances, the possibility that stem cell-derived embryos will one day become living animals is increasing. “In theory, if you have all the right cell types … you can go further,” says Rossant. “There’s no way it won’t happen.”
However we describe blastoids and other embryo-like structures, it’s time to start taking control of how we grow and study them. Rossant is one of several scientists I’ve spoken with who agrees that, given how similar these embryo-like structures are, they should probably be subject to the same rules and regulations that cover research on normal embryos.
“The biggest risk… is if we have a very fast rogue player. [with human cells]And it created something that created civil disobedience,” says Morris.