Any recessive trait will need two recessive genes of an organism to manifest that characteristic. Image courtesy of Wikimedia Commons. Most X-linked traits in humans are recessive. When sex cells fuse in a process called fertilizationthe resulting cell zygote receives one sex chromosome from each parent cell.
An example of this can be seen in hemophilia. Fragile X syndrome is a condition that results in learning, behavioral, and intellectual disabilities. You will be a patient of tritanomaly if your blue cone cells aren't fully functional. Affected individuals may not see the number 6.