"that a man from " He said: 'Yes." He said: "Then what are their colors?" He said: "Red." He said: "Is there a gray one among them?" He said: "Yes, there is a grey one among them." He said: "From where does that come?" He said: "Perhaps it is hereditary." He said: "Then in the same way, perhaps it is his heredity."

This Hadith is Hasan Sahih.

Jami` at-Tirmidhi Book 31, Hadith 4