Depends if we are acknowledging a difference between:
Gene Therapy - Which implies that we are using genetic manipulation to fix genetic errors. Effectively, "healing" people with a genetic disorder.
and
Gene Engineering - Which ultimately is trying to create Humanity+.
There is nothing wrong with Gene Therapy from a theological standpoint.
Gene Engineering is where issues come into play. Personally, I say avoid that shit like wildfire. I don't believe there is such a thing as a "upgrade" to biology. Just tradeoffs we dont yet understand.