What they bring is suffering. No one ever wishes for a non responsible child. No one wants their child to be the "special one". No one wants all the hardship it brings. Even the proxy Munchausen prefers to have a functioning level so they don't have to do the work.
No one wants to be tested by a "greater power" (random gene selection) especially not the sick little being that Teoretically Could be cured but there are people like you who like to decide stuff for OTHERS.
How much time do you spend at orphanage with special needs?
How much contact do you have to sit on the high horse and try to be god?
How much time and money do you spend on personally helping the kids?
How many diapers did you change to get to this opinion?
Gene thereapy has a right to exist. And with everything else as humans, we will abuse it to the limit.
The problem is not the cure but the mindset. And your pretentious preaching won't bring conversation only suffering. You are not helping.