Some problems come to mind: - this is performing an irreversible procedure on a person without their consent. Justifiable for a disease but less so for vanity

Some problems come to mind: - this is performing an irreversible procedure on a person without their consent. Justifiable for a disease but less so for vanity traits. - genes are pleiotropic and modifying multiple genes could have unexpected effects. An easy example is that taller people have a higher risk of cancer. Barring some great advance in predicting the effects of genetic changes, this will remain a problem. - it has a homogenising effect, optimising for traits a culture finds appealing and that can be easily measured. You will eventually get a eugenic army that all look like swimwear models and score highly on IQ tests. At the same time, I think that modifying the organism is the only way to get rid of diseases like heart disease and cancer.