From Kernel.Org, home of the Linux kernel. It clearly says quote “Linux is a clone of the operating system Unix” unquote, right on the front page. Whine some more but these are the facts.
What is Linux?
Linux is a clone of the operating system Unix, written from scratch by Linus Torvalds with assistance from a loosely-knit team of hackers across the Net. It aims towards POSIX and Single UNIX Specification compliance.
You can quote it but you don't truly understand it. There are two standards, and being certified in the latter makes it UNIX™. The fact that is a clone (as is Minix, BSD, etc.) is irrelevant. All Torvalds has to do to make the kernel compliant is make some changes and control future kernel changes to keep it that way. As for the whole OS Red Hat or Novell could make sure the rest of their distros are compliant, then they can advertise Linux as UNIX™. I'd love to see the look on your face if that happened.