Sure, as the Nature news piece I linked to mentioned, there is evidence for both genetic and environmental factors playing a factor in myopia (as in the case of most traits). For example, the piece cites twin studies from the 1960s showing that myopia has a genetic component. However, there is also strong evidence for an environmental component. For example: These observational studies are backed up by more recent randomized clinical trials experiments where increasing the time spent outdoors lessened the incidence of myopia in children compared to a control group (see the Nature piece for a more detailed description of the experiments). So, in some populations (such as the Navajo), genetics will the be primary cause of myopia, but for many other populations, environmental effects seem to be a major factor. Both are very good points. As I mentioned previously, I bring these arguments up mostly as a devil's advocate to illustrate some of the important ethical questions that others have brought up with regard to germline gene editing. I have no problem with research on embryos (for example, in the future, cloning an individual's cells to generate genetically identical embryonic stem cells for clinical uses). However, when generating embryos that will become a person, I think scientists and physicians have a responsibility to exercise caution in performing any procedures that carry risks of harming the embryo. While embryos do not have personhood under law, embryos destined for implantation probably should have some sets of rights to consider. Clinical research operates on the principle of informed consent, though we recognize that this is not always possible (e.g. in the case of research on children). Thus, when the subject cannot give informed consent, special precautions should be taken to manage the risks involved (e.g. having an Institutional Review Board scrutinize the proposed procedures with the interests of the unborn children in mind).