There are no mistakes , everything is as it should be in this year 2018. In 2018, God wanted there to be a certain amount of humans with whatever problems they have; he wanted that to exist on earth, and its exactly what has happened. Human history is simply the unfolding of God's will.
So why does god keep making deformed/retarded/in constant pain babies?
So that he can completely heal them and change them in his future; all you see is the now, because we are " Now present day creatures", God is dealing with a future where all these babies will be changed, as will all humans. This removes the sting out of your gripe with God, but you don't want to let that gripe go, so you cannot look into the future. Any human that looks into the future of God, can only see complete healing.. And they would have to release all gripes with God.
But you NEED your gripes, because of the giant chip on your shoulder. And I understand that need; because you don't know the true power of God and his true intentions for humanity.