Male mammals carry XY sex chromosomes - female mammals carry XX sex chromosomes. Inherited disorders are caused by faulty genes on these chromosomes.
Different versions of a gene are called alleles, and these alleles can be dominant or recessive.
A gene is a short section of DNA. Each gene codes for a specific protein by specifying the order in which amino acids must be joined together.
Gametes are sex cells. The male gametes are the sperm, and the female gametes are the eggs.