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: "Every child is born upon the fitrah (natural disposition); his parents make him a Jew." Then he narrated the hadith.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12139