1. Sex linked traits are produced by genes found on the sex chromosomes (X and Y). The females are homozygous x, so they have 2 x chromosomes (XX). Males are heterozygous x, so they have 1 x chromosome (XY). Most of the sex-linked traits are X linked because the X chromosome is larger than the Y chromosome and it contains more genes than the Y chromosome. A woman can be a carrier because since they have two X chromosomes. In women, a recessive allele on one X chromosome is often masked in their phenotype by a dominant normal allele on the other. This explains why women are frequently carriers of X-linked traits but more rarely have them expressed in their own phenotypes