Al-Hasan (may Allah have mercy on him) narrates from Sayyiduna Umar (may Allah be pleased with him) that two men had intercourse with a slave-girl in the same period of purity. She gave birth to a boy, and the matter came to Sayyiduna Umar (may Allah be pleased with him). Sayyiduna Umar (may Allah be pleased with him) sent for three physiognomists. They all agreed that the resemblance was with both of them. Sayyiduna Umar (may Allah be pleased with him) also judged by the signs and said: If black, yellow and spotted dogs mount a bitch, (her pups) bear a resemblance to each one. I had never seen this (among people), but now I see it. So Sayyiduna Umar (may Allah be pleased with him) made the two of them heirs of the child, and the child will be their heir; and he belongs to whichever of them survives.
Both of these narrations are munqati' (broken in their chains).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الدعوى والبينات / 21267