Dawud bin Abi Hind (may Allah have mercy on him) narrates from al-Sha'bi (may Allah have mercy on him) concerning the mudabbarah and the umm walad (a slave-girl who has borne her master's child): the children of both of them have their status.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المدبر / 21588