Genes that are carried by either sex chromosome are said to be sex-linked. Men normally have an X and a Y combination of sex chromosomes, while women have two Xs. Since only men inherit Y chromosomes, they are the only ones to inherit Y-linked traits. EdrawMax and EdrawMax Online are the best free online pedigree chart makers currently ruling the market. These free online pedigree chart makers offer tons of customizations. As the below sex-linked inheritance diagram suggests, in males (who have only one X chromosome), an alteration in the only copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), one altered copy of the gene usually leads to less severe health problems than those in affected males, or it may cause no signs or symptoms at all.