Y'know, you made me think: Khan sounds Jewish--mebbe ol' Genghis was one of John Effin Kerry's ancestors.
I believe I read on a thread yesterday that Kerry's ancestors changed their last name from Kohn (pronounced Kahn LOL) to Kerry.
You're correct about Jenjis being jewish....History has recorded his name wrong - it was Jenjis Cohen - which sounds like Kahn when spoken with an uppity bostonian accent.