I do disagree with Franklin Graham suggestion that becoming a christian in “in your DNA”. If one is a christian they are christians because God has drawn that person unto Him. Although one might say that the DNA line could suggest that Franklin believes that whether one becomes a christian or not is determined by DNA might suggest that Franklin is a armchair Calvinist.
re-read the quote. you are taking his quote out of context. He is saying that Palin is a Christian to her core. Not that she was a Chistian because of her DNA.....
Many are called, few are chosen. Seems to fit here.