Gentile is not a term used in Noah's time. He's a human. The term gentile can apply only when it is relative to the Jews.
If he was jew, I expect his descendants were jews too. Unless you can undo your jewness in one generation, you are a jew too,like everybody else.
You seem to confirm that X is jew if He is related to a jew. If Noah family is jewish,it follows by recursion that we are all jews.
So, are you a jew. If not,why not?
Ciao
- viole