This troubles me more than a little.
I recall reading about the “HELA” cells that contaminate just about every lab in the world. A woman named (I believe) Henrietta Lacks had, decades ago, a particularly virulent form of cancer. So, before her death, they took and cultured some of the cells for study. Cancer cells, of course, are, by their nature “new syntheses” of otherwise normal cells.
Those cells (Now called “HELA” cells after Henrietta Lacks) are so virulent that they contaminated the lab and everything that came into or went out of that lab. Genetic researchers all over the world, to this day, have to be careful or they will find that every culture ends up containing nothing but HELA cells, no matter how it starts out.
There are, of course, some who believe that diseases like HIV and Ebola and Marburg are new combinations or mutations. Maybe so, maybe not. But even with those, their DNA can be studied and are (at present) predictable in their configuration. So, when it comes to potential treatments and cures, at least there is some possibility of dealing with something fairly stable and whose characteristics, however deadly, are known.
But when scientists take snippets of DNA from here and recombine them and insert them in an egg from there, all without having any idea what its living characteristics might be, one has to wonder how they know they’re not creating another HELA; perhaps a HELA that has even worse consequences than contaminating petri dishes worldwide like the original HELA does.