It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever is born is born upon the fitrah (natural disposition); then his parents make him a Jew or a Christian, just as animals give birth to their young. Do you ever find any with its ear cut off, until you yourselves cut it?" They said: "O Messenger of Allah! What do you say about one who dies while still young?" He (peace and blessings be upon him) said: "Allah knows best what they would have done."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12140