You then rate other females, 1-10, not just on her looks, but her ability to love a man.
A McAdams 10 is a woman who is marriage material.
Stewart: Who was that girl you were talking to?
Kevin: Oh, don't worry, McAdams 4.
Kevin: That girl.... would marry out of 10?
Stewart: McAdams 9 mate.
Kevin: She's a McAdams 10.