But the difference here is that, to the best of my knowledge, there's nothing particularly difficult about CRISPR in humans. It's routine in other mammals and had previously been done on human embryos. The thing holding everyone back was ethical concerns and the possibilities of off-target effects, side-effects of the mutation, etc. So I'd err on the side of assuming they did do it.
It's worth noting that none of the moderators or questioners at the talk expressed any skepticism that He had done it. They all took for granted He had.
It's really not that implausible a thing to do, you know. People have been editing human embryos with CRISPR since at least 2014. And He has past experience, it seems, and had networked a fair amount and seemed to know what he was doing. George Church also has said that he's seen some of the data and it looks right to him. Combine that with all the data on the slides, and while you can debate the ethics or how useful it would be or how well it actually worked, it seems increasingly plausible that he did something like what he claimed, and he's not simply faking it all.
