In 1978, Louise Brown became the first child born after being conceived through in vitro fertilization, or IVF. Time ran a cover playing on Michelangelo’s Creation of Adam, with the hands of God and man nearly touching, and a test tube in between them. (Brown is widely called the first “test tube baby,” though the devices weren’t used in her conception.)

But it wasn’t all open hands when the news broke. Some feared scientists were playing God and meddling in things they shouldn’t be. Others saw a significant scientific breakthrough that would enable many people to become parents who otherwise may never have been able to. And that’s what has happened. In the 40 years since Louise Brown, more than 8 million babies have been born through IVF.

Last week, news broke that a pair of twins whose DNA had been altered were born in China. If true, they would be the first humans born using CRISPR gene-editing technology. The babies were modified to be resistant to HIV, according to He Jiankui, the scientist behind the project. This has been compared to Brown’s birth, but the reaction hasn’t been the same.

The implications of gene-edited babies are quite different from those of IVF. The unknowns with CRISPR are vast. Some worry the children may be more susceptible to other diseases. There are questions about the safety of conceiving edited children. Scientists have largely called He’s work unethical. They question whether it was even medically necessary, and why it was done with such secrecy.

“There are serious unanswered questions about the safety of embryo editing and a need to make sure that such research is conducted in a transparent, monitored way so the technology is not misused,” The New York Times reports, noting that China has suspended He’s work.

“The genetic editing of a speck-size human embryo carries significant risks, including the risks of introducing unwanted mutations or yielding a baby whose body is composed of some edited and some unedited cells,” writes Antonio Regaldo in the MIT Technology Review. “Data on the Chinese trial site indicate that one of the fetuses is a ‘mosaic’ of cells that had been edited in different ways.”

“One day it may make sense to edit an embryo — to cure genetic diseases, say,” The Economist writes. “That day has not arrived.”

But the era of modified humans has arrived. He’s work cannot be undone, and the line can’t be uncrossed. How, then, should the world move forward? The Economist has a suggestion:

It may even be that editing will one day be used on embryos to enhance genomes (to make people cleverer, say), rather than to cure disease. But that requires regulators, policymakers, scientists and civil society to think through deep ethical questions.

Show produced by Avery Kleinman.


  • Carl Zimmer Science Columnist, The New York Times; Author, "She Has Her Mother’s Laugh: The Powers, Perversions, And Potential Of Heredity"; @carlzimmer

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