By contrast, we could also end up with humans that are stronger, smarter, or are better adapted to a changing environment. In routine IVF, parents select for t

By contrast, we could also end up with humans that are stronger, smarter, or are better adapted to a changing environment. In routine IVF, parents select for the strongest embryo to implant. This cannot happen in the case of traditional embryo development, where the released egg meets the sperm. The assumption that IVF could produce weaker humans is an assumption rooted in what? Sci fi?