Yahya bin Abd al-Rahman bin Hatib narrates from his father that two men came to Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) with a dispute over a child from the Jahiliyyah. One would say: He is my son, and the other would say: He is my son. Sayyiduna Umar (may Allah be pleased with him) sent for a physiognomist of Banu al-Mustaliq, who looked at the child and said: These two both share in him. Sayyiduna Umar (may Allah be pleased with him) struck him with a whip and said to the child: Go with whichever of them you wish. So the child went with one of them. Abd al-Rahman said: The child sided with one of them and went off. And Sayyiduna Umar (may Allah be pleased with him) said: May Allah destroy the Mustaliqi!
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الدعوى والبينات / 21261