Christians who look at the 'big picture' through the history of the Bible, founded in Genesis, have an advantage in being able to judge such matters. Where technological 'fixes' are applied to people's bodies, if the purpose is to bring about healing, this is unlikely to be 'opposing God'. Following Christ's example as the great Healer, it can always be seen to be blessed when fighting against the disease resulting from the Curse. Where God's revelation to humanity, the Bible , is rejected as authoritative, there can be no basis outside of the shifting sands of fallible human opinion. Genetic engineering has nothing to do with evolution.
Evolution involves things happening 'by themselves'.
Deliberately manipulating the genetic code in a plant, for instance, involves intelligent effort and purpose, the very opposite of Darwinism. As indicated earlier, genetic engineering may be used for good in reversing harmful mutations that are the result of the Curse, or it could conceivably be used for evil. For instance, it could be used for the purpose of one human 'having dominion' over another, something that is excluded from the Genesis mandate to 'subdue the earth'. Genetic engineering of plant crops to get better yields, for instance, may not be morally wrong biblically, but it involves 'wisdom issues'. I.e. in a particular instance, it may be wise or foolish.