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.
