2,237. A Confirmed Kohein Who Returns From a Foreign Land
Hilchos Issurei Biah 20:6
Let’s say that a confirmed kohein leaves for another country along with his wife, who is known to be of halachically fit lineage. If he returns with her and children who treat them as parents and he says that this is the woman who left with him and his children with her, he need not bring witnesses to testify about them. If he says that she died and these are her children, he must bring witnesses to testify that these are his children but he need not bring witnesses to testify that his wife was halachically fit since that was established before she left.
Hilchos Issurei Biah 20:7
Let’s say that a confirmed kohein leaves for another country and returns with a wife and children, saying that he married this woman and these are his children with her. In such a case, he must bring proof that the woman is halachically fit, though he need not bring witnesses that these are her children so long as they treat her as their mother. If he returns with two wives and brings proof about one, he must bring proof about the children, even if they’re very young and treat her as their mother. This is because they might be the children of the other woman but relate to this woman of known lineage as a mother.