After the suicide of his Aunt Harriet and the death of her baby girl, David becomes extremely apprehensive about his abnormality. Fearful of being a mutant, he prays that he will lose his ability to be clairvoyant, and that he will wake up and be like everyone else.
...please, please, God, let me be like other people. I don't want to be different. Won't you make it so that when I wake up in the morning I'll be just like everyone else, please, God, please!'
It is tragic that David feels that his gift of communicating telepathically with others is a curse and not something of which to be proud. Sameness is something demanded of controlling governments, not free ones. But, when David talks with his Uncle Axel, his uncle mentions that physical deviations may, indeed, be detrimental to the race, but when one has more powers of the mind, these should be fostered. He repeats what he was told by a doctor on his ship once:
"That was the only thing he [man] could usefully develop; it's the only way open to him — to develop new qualities of mind."
And, it is because mental powers are useful and help advance civilization that it is Uncle Axel says it is wrong for David to pray to be like everyone else. He tells David,
To pray God to take it away is wrong; it's like asking Him to strike you blind, or make you deaf.