Illinois Department of Public Health Vision Training Practice Exam – Prep and Study Guide

Color deficiency, commonly known as color blindness, most frequently affects males due to its genetic transmission. The condition is often linked to the X chromosome, with males having one X and one Y chromosome, making them more susceptible to inheriting X-linked traits. If a male inherits a mutated gene from his mother on his single X chromosome, he will express the color deficiency. In contrast, females have two X chromosomes, so they would need to inherit the mutated gene from both parents to express the condition, which significantly reduces its prevalence among females. This genetic aspect explains why color deficiency predominantly affects males rather than females or others.