What the Law and Bioethics Tell Us About Synthetic Human Embryos

A synthetic embryo can now be constructed from very early pre-embryonic cells – without the need for an egg or sperm. These were initially created in mice. In April, researchers in China published about their creation of synthetic monkey embryos. In June, it was reported that the first synthetic human models were apparently created. This development throws a moral monkey-wrench into the current moratoria on embryonic research after 14 days. But there are more problems ahead.

Two weeks – the 14-day Rule

Of immediate concern are the ramifications of the 14-day rule, which imposes a (voluntary in the U.S.) moratorium on experimentation on human embryos older than 14 days; after that, they must be terminated. Strictly speaking, at this point, the fertilized egg (zygote) is called by various names, e.g., blastocyst and a “morula” (“little cherry”) because depending on the stage of development, that’s what the entity resembles. This zygote does not achieve full “embryo” status until day 14 after fertilization, the beginning of “gastrulation.”

In biological terms, the 15^th day of embryo development is the point when...