The theme of Brave New World is not the advancement of science as such; it is the advancement of science as it affects individuals

Science has basically replaced the "family" unit. Embryos are developed in bottles, children are raised and conditioned by the state. It has ruined the physical meaning of a "family". Science is a good and a bad meaning. In the book it's bad because "science" is used for cloning children and producing/raising them the way people want them to be. Children can be raised that same way without being cloned or trained by the state, that's what parents are for. Science has also provided safe lines for emotional and human desires such as, Soma. Soma placates anger, hostility and wants. Genetic engineering allows the intelligence necessary for each caste and sub-caste to fill its place is society.