It is possible to replace several faulty genes through gene therapy. The question I have is, can we replace all faulty genes by replacing our whole genome? There are several problems of course, e.g. we currently don't know if something is really faulty. For some genes we do know, that they cause several problems but for many others we don't. Let's suppose that this information is available. We have a perfectly healthy human with a perfect genome. The genome has been optimized with a quantum computer that took into account nearly all possibilities and knows exactly what drawbacks could arise from certain manipulations (e.g. a person with allergies might be less prone to certain types of cancer, is this trade-off worth taking?). If this sounds unrealistic to you, please think of a very healthy normal person, who is supposed to live long. Would it be possible to replace the whole genome of an ill person, with the whole genome of a healthy person? In other words, is it possible to not only replace a few genes but several thousand genes at the same time?