It is narrated from Sayyiduna Ali (may Allah be pleased with him) that once a mule was presented to the Prophet (peace and blessings be upon him) as a gift. We said, "O Messenger of Allah! If we mate such-and-such donkey with such-and-such mare and an animal like this is produced, what about that?" The Prophet (peace and blessings be upon him) said: "This is done by those who are ignorant."