10 trillion cells? As the British say, not bloody likely.
“Know you not that the unjust shall not possess the kingdom of God? Do not err: neither fornicators, nor idolaters, nor adulterers, [10] Nor the effeminate, nor liers with mankind, nor thieves, nor covetous, nor drunkards, nor railers, nor extortioners, shall possess the kingdom of God.”
1 Cor 1:6:9-10
They are starting to treat sickle cell anemia by altering the DNA of bone marrow cells inside the patient.
Believe it or not they are using a modified HIV virus (neutered to a non-infectious non-pathogenic shell of itself, what could possibly go wrong?) as a carrier for the altered gene.