Omigosh, did you only just now find out about the MacBeth influence? That's where Tolkien got Eowyn killing the Nazgul king from too! Because "I was born by C-section" is an incredibly lame solution to the "No man of woman born shall harm MacBeth" prophecy when women are RIGHT THERE. XD

I kinda think there's another MacBeth reference in LoTR, too, but I can't remember what and Google is not producing it for me, so maybe not.