They have not yet authorized it for human testing and Congress has banned it since its a genetically modified embryo. The reason why they’re coming for him is because in an article he published, Zhang claimed that the embryo was made in the U.S. which is a big no-no.
“Zhang used the technique last year in an attempt to prevent Leigh syndrome, a severe neurological condition that affects at least one in 40,000 newborns. The mother he treated had previously miscarried four times and given birth to two children, one of whom survived less than a year and another lived for only 6 years, both due to the syndrome.
On April 6, 2016, the mother gave birth to a reportedly healthy baby boy. “Transfer of the [normal] embryo resulted in an uneventful pregnancy with delivery of a healthy boy at 37 weeks of gestation,” wrote Zhang and his co-authors in the published study.”