Final answer:
Red-green color blindness that Josh has is a sex-linked genetic disorder which is caused by a recessive gene on the X chromosome, affecting predominantly males.
Step-by-step explanation:
Josh has red-green color blindness, which is an example of a genetic disorder. Red-green color blindness is a common inherited trait and is the most common type of color deficiency. This condition is a sex-linked disorder, specifically linked to the X chromosome, which explains why it predominantly affects males. The disorder is known to be a sex-linked recessive trait.
There are various forms of this color deficiency, including Deutan and Protan types of red-green colorblindness. The prevalence of red-green color blindness varies by ethnicity, with around 8% of European Caucasian males affected. Females are much less likely to have red-green color blindness due to the presence of two X chromosomes, which allows a normal gene on one X chromosome to compensate for the defective gene on the other X chromosome.