Musannaf Ibn Abi Shayba 26:288

'Abbad ibn al-'Awwam narrated to us, from 'Umar ibn 'Amir, from Hammad, from Ibrahim, from 'Abdullah, who said regarding the child of the *li'an* (mutual imprecation): His entire inheritance is for his mother. If he has no mother, then it is for his agnatic relatives (*'asaba*). And Ibrahim said: His entire inheritance is for his mother, and her agnatic relatives are responsible for his blood money (*diya*). The same applies to the child of adultery, and the child of a Christian woman whose mother is a Muslim.