Coffee addict: if she (the mother) had her (the child) before she was M’gayer- then the child would have been born to a non-jewish mother and would have had to m’gayer herself… so then the child would be a Ger.
So, I think it’s obvious that the poster’s question is about a mother who was M’gayer and then had the child. Which means, that for the purpose of this discussion, the Kohen can marry this child, just like he could marry any child born to any other Jewish mother.
Correct?
well then she was born to a jew, and the kid would be jewish and is like any other jew so the kid would be muttar (like you clearly stated) so the question doesn’t start