Abu Hurayrah (may Allah be pleased with him) said: A Bedouin came to the Prophet (peace and blessings be upon him) and said: My wife has given birth to a black boy. He (peace and blessings be upon him) asked: "Do you have camels?" He said: Yes. He (peace and blessings be upon him) asked: "What is their colour?" He said: Red. He (peace and blessings be upon him) asked: "Is there any ash-coloured one among them?" He said: Yes. He (peace and blessings be upon him) asked: "Where has that come from?" He said: Some ancestral strain must have drawn it. So he (peace and blessings be upon him) said: "Then perhaps some strain has drawn this son of yours too."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / 17141