How do fertility treatments help get rid of disease and disability and is this eugenics?

PGD 4 some diseases. In vitro fertilization can be combined with preimplantation genetic diagnosis where we test embryos for a genetic disorder before replacing disease-free embryos or carriers back into the mother's uterus. This can be done for any known single-gene disease like cystic fibrosis. Most diseases involve multiple genes, like diabetes. So a very limited form of eugenics for individual families at risk.