Well, maybe next best thing is a link to a different article?

Tetrachromacy: A World of Colour

which says, amongst other things,

"This means tetrachromacy is only possible for most women, who have two X chromosomes, and men with Klinefelter syndrome, who have two X chromosomes and one Y chromosome. Therefore, most men, who only have one X chromosome and one Y chromosome, cannot be tetrachromats."


And if that sounds simple to you,
well, it's Greek to me ...