Why do sex linked traits follow follow differnt patterns of in heritance than other traits?

Answer 1

The short answer is because these traits are linked to the sex chromosomes and not the autosomes.

Genetic females are XX. The twin X's are a true homologous pair, and inheritance follows the normal pattern of AA-Aa-aa. Masking recessive traits with a dominant allele can occur. The XX female also has no probability of showing a Y-linked trait simply because she has no Y chromosome.

Genetic males are XY. This combination is NOT homologous, X and Y do not code for the same genes. In genetic males, X-linked or Y-linked traits have no chance of being masked, the pattern is A-a only.