5 people to save the world.

[Slamz]

Who says they have to be from Earth?

Vllad's dictionary!

"3. human beings, as distinguished from animals or other beings."

Creatures born "a long long time ago in a galaxy far far away" would probably fall under "other beings".

Although I suppose if they were genetically identical, you could argue that we must have somehow had the same origin and are therefore all the same species.

I choose Samantha Carter to resolve this dispute.