Sex-linked single-gene disorders are typically passed down from mothers to sons.

Question

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Sex-linked single-gene disorders are caused by genes located on the sex chromosomes, which are inherited differently by males (XY) and females (XX). Sons inherit their X chromosome from their mother, so if she carries a mutated gene on her X chromosome, there is a 50% chance that her son will inherit it and therefore be affected by the disorder. Daughters have two X chromosomes and would need to inherit two copies of the mutated gene to be affected, so they are less commonly affected by sex-linked disorders.

Sex-Linked Single-Gene Disorders Are Typically Passed Down from Mothers to Sons