Earlier quoted context omitted.
Back in the days of Mac OS classic, there was a tool called ResEdit. You could use it to explore and modify apps. Or the core OS. While it was running. It warned you this was a bad idea, but I did it anyway. It took ten years before I saw a computer lock up that hard again. That’s how I see humans DIY hacking their own genome. If you’re lucky you’ll get what you were after. If not, you now have sexuality transmissibl…
It doesn't really work like that though. The genes that cause much of your form dictate growth processes between embryo and adulthood. If you could change them everywhere you wouldn't change at all. But it's also not how CRISPR/CAS9 works either. Gene therapies usually involve a process of extracting stem cells, modifying a small number of them in vitro, growing them, and then either using them to grow tissues out of…
I don't think that's what they were referring to. It seems that the concern is you make an edit, it is unsuccessful in implementing whatever you wanted but also breaks something critical (e.g. proper skull formation), and that gene is passed to your children who then suffer the consequences. That seems feasible to me, but I'm not a bio expert, don't play one on TV, and haven't stayed in a Holiday Inn in years.