聽is Distinguished Research Professor, Emerita at聽听补苍诲听聽is a聽Professor in the Faculties of Law and Medicine at聽.
On June 14, 2023, developmental biologist Magdalena 呕ernicka-Goetz presented her research on creating human embryos using stem cells at the (ISSCR).
This research could , help us learn how to prevent early miscarriages, lead to improvements in fertility treatment, and 鈥� perhaps 鈥� .
Beyond the limits
Synthetic human embryos 鈥� also called embryoid bodies, embryo-like structures or embryo models 鈥� mimic the development of 鈥渘atural human embryos,鈥� those created by fertilization. Synthetic human embryos include the 鈥�.鈥�
Though research involving natural human embryos is legal in many jurisdictions, it remains controversial. For some people, research involving synthetic human embryos is less controversial because these embryos cannot 鈥渄evelop to the equivalent of postnatal stage humans.鈥� In other words, these embryos are non-viable and cannot result in live births.
In addition, some maintain that the creation of synthetic human embryos would allow for that typically applies to natural human embryos.
But would it?
Laws in the United Kingdom
The at the ISSCR meeting took place in the United Kingdom. It was conducted in accordance with the , with the approval of the U.K. .
U.K. law limits the research use of human embryos to . An embryo is defined as 鈥�.鈥�
Synthetic embryos are not created by fertilization and therefore, by definition, the 14-day limit on human embryo research does not apply to them. This means that synthetic human embryo research beyond 14 days can proceed in the U.K.
The door to the touted potential benefits 鈥� and ethical controversies 鈥� seems wide open in the U.K.
Canadian law
While the law in the U.K. does not apply to synthetic human embryos, the law in Canada clearly does. This is because the legal definition of an embryo in Canada is not limited to embryos created by fertilization.
The Assisted Human Reproduction Act (the AHR Act) defines an embryo as 鈥�, excluding any time during which its development has been suspended.鈥�
Based on this definition, the AHR Act applies to embryos created by reprogramming human embryonic stem cells 鈥� in other words, synthetic human embryos 鈥� provided such embryos qualify as human organisms.
A synthetic human embryo is a human organism. It is of the species Homo sapiens, and is thus human. It also qualifies as an organism 鈥� a life form 鈥� alongside other organisms created by means of fertilization, asexual reproduction, parthenogenesis or cloning.
The definition of an organism does not stipulate a specific means of creation and so can include creation by means of reprogramming embryonic stem cells.
Limitations
Given that the AHR Act applies to synthetic human embryos, there are legal limits on their creation and use in Canada.
First, human embryos 鈥� including synthetic human embryos 鈥� can only be created for the purposes of 鈥�.鈥�
Given the state of the science, it follows that synthetic human embryos could legally be created for the purpose of improving assisted reproduction procedures.
Second, 鈥渟pare鈥� or 鈥渆xcess鈥� human embryos 鈥� including synthetic human embryos 鈥� originally created for one of the permitted purposes, but no longer wanted for this purpose, can be used for research. This research must be done in accordance with the which specify that consent must be for a 鈥渟pecific research project.鈥�
Finally, all research involving human embryos 鈥� including synthetic human embryos 鈥� is subject to the 14-day rule. The law stipulates that: 鈥�, excluding any time during which its development has been suspended.鈥�
Putting this all together, the creation of synthetic embryos for improving assisted human reproduction procedures is permitted, as is research using 鈥渟pare鈥� or 鈥渆xcess鈥� synthetic embryos originally created for this purpose 鈥� provided there is specific consent and the research does not exceed 14 days.
This means that while synthetic human embryos may be useful for limited research on pre-implantation embryo development, they are not available in Canada for research on post-implantation embryo development beyond 14 days.
Prospects for expansion
Proponents of synthetic human embryo research beyond 14 days may argue for a different interpretation of the law and insist that synthetic human embryos are not 鈥渉uman embryos鈥� as defined in the AHR Act. But this looks to be an impossible task.
Alternatively, they may insist there is an important moral distinction between natural and synthetic human embryos because synthetic human embryos lack the potential to become live born humans. This means they fall into the category of non-viable human embryos.
It is not the case, however, that all natural embryos are viable embryos, and that all synthetic embryos are non-viable embryos. There are non-viable natural embryos such as , where more than one sperm enters the egg during fertilization.
And one day, synthetic human embryos may be viable embryos. In any case, in Canada, viable and non-viable embryos are legally equivalent. They are subject to the same rules, including the 14-day limit.
This leaves proponents of synthetic human embryo research beyond 14 days with the need for an alternative argument. But any argument will have to overcome the political reality that the federal government is unlikely to open up the Pandora鈥檚 box of amending the AHR Act.
It therefore seems likely that synthetic human embryo research will remain limited in Canada for the foreseeable future.
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