Muwatta Imam Malik (Riwayat Yahya)

It is narrated from Sulayman bin Yasar that Sayyiduna Umar (may Allah be pleased with him) used to attribute the children of the Jahiliyyah (pre-Islamic period) to the one who claimed them in the time of Islam (i.e., he would establish lineage accordingly). Once, two men came claiming a boy. Sayyiduna Umar (may Allah be pleased with him) called a qā’if (an expert in physiognomy). The qā’if looked and said: Both of them share in this boy. Sayyiduna Umar (may Allah be pleased with him) struck the qā’if with a whip, then called the woman (i.e., the boy’s mother) and said: Tell me your situation. She pointed to a man and said: He used to come to me while I was among my people’s camels, and he would not leave me but rather cling to me (i.e., he used to have intercourse with me), until both he and I thought I might become pregnant. Then he would leave and I would menstruate. Then another man would come, and he too would have intercourse with me. I do not know which of the two this child’s semen is from. The qā’if, upon hearing this, became overjoyed (because his statement turned out to be true). Sayyiduna Umar (may Allah be pleased with him) said to the boy: You have the choice; you may affiliate yourself with whichever of them you wish.