2,236. The Son of a Confirmed Kohein

Hilchos Issurei Biah 20:4

If two witnesses testify that they saw someone eating Biblical-level trumah, his status as a kohein is considered established. We don’t consider someone to be established as a kohein based on him reciting birkas kohanim (the priestly benediction), receiving the first aliyah, being given trumah in the granary, or based on the testimony of one witness.

Hilchos Issurei Biah 20:5

If a kohein whose lineage is confirmed says, “This son of mine is a kohein,” the son is not considered a confirmed kohein unless the father brings witnesses who testify that the child is his son.