What is the ruling on the conversion to Islam of minor girls from among the Jews and Christians?

If the question is about the حكم (ruling) on the Islam of a child from the People of the Book: A child who is not discerning (غير مميز) is not held accountable for his statements or actions. As for a discerning child (الصغير المميز), scholars have differed regarding the ruling on his Islam. By original principle, a child follows the better of his two parents in religion. So, if one of his parents is Muslim, he is ruled to be Muslim in accordance with that parent, and this is the most preponderant opinion.