User blog comment:MetallicArcher/A Season for each Kingdom/@comment-4010415-20151127231427/@comment-24994749-20151128001423

Actually, women can be colour blind. The thing is that the genetic defect that causes colour blindness is on the X chromosome.

Since men have only one X, when they carry the gene they are affected, but they will also only pass it down to female offspring.

Meanwhile, as women have two XX chromosomes, as long as they have one healthy copy of it from either parent, they will be healthy carriers. If they have a daughter and the father is not colour blind, there is a 50% chance (more or less) that the daughter will be a healthy carrier, too. If they have a son he will either be colour blind or not.

If the mother is a healthy carrier and the father is colour blind, the daughter might be a healthy carrier or be colour blind.

This is always talking about colour blindness that is genetic, other stuff can make you go colour blind, like damage to the eye or the optic nerve... Which reminds me I did use to have a brain cyst that pressed on my optic nerve and it did also use to screw up my vision to the point I needed reading glasses... well f*** that cyst it deserved being removed.