Unlocking the black box of early human development without an egg, sperm, or womb

Synthetic embryos push ethical boundaries Scientists explore human development beyond natural limits, raising ethical and legal questions.

Stem cell biologist Jacob Hanna has received a lot of worldwide attention since his team at the Weizmann Institute of Science in Israel created a synthetic human embryo.

He was at a human reproduction conference in Montreal this week to discuss his ground-breaking work.

The living structure, made from stem cells cultured in a lab, was created without an egg, sperm, or a womb. The model gives a window into the earliest stage of development when cells are rapidly multiplying.

“I call it the big drama, when a ball of stem cells becomes an organ filled embryo. And the rest of pregnancy is just growth,” he said.

The first month is also when most miscarriages happen, and developmental defects occur.

Studying this period is almost impossible since embryos are too small to be seen via ultrasound and most countries, including Canada, do not allow embryos in a lab beyond 14 days.

To circumvent the technical and ethical constraints, Hanna and his team produced a synthetic model, using stem cells from different species that could be grown in a lab and generate all the components of an embryo, including the placenta and the yolk sac.

Sophie Petropoulous, the Canada Research Chair in Functional Genomic of Reproduction and Development, said Hanna’s research is already impacting her own work in studying infertility at the Université de Montreal.

“It's really one of the first models that lets us understand the process of implantation and onward to the period that we call the black box, that in the human we don't understand,” she said.

While the research in this early period is rapidly developing, there is a push within the scientific community to lift the 14-day restriction, according to Canadian bioethicist Francoise Baylis.

“Now scientists are saying, ‘well, why can’t I go beyond 14 days?’” Baylis said.

“I can tell you about all the benefits that I could deliver as a scientist if you would let me go beyond 14 days.”

But Baylis said that only frames the issue from the scientific standpoint, and not the greater issue of how this impacts humanity.

Lifting the restrictions would mean changing laws, and Baylis said the public would have to be involved in any decision making that could have big implications.

“Part of what we’re looking at is potentially changing us as a species,” she said.

Hanna said he supports ethical constraints but added the work being done in this field could also have life changing benefits such as curing disease and preventing miscarriage.