X-Linked Inheritance

X-linked recessive conditions (such as hemophilia A, Duchenne muscular dystrophy, and fragile X syndrome) are carried on the X chromosome. Carrier women (with one affected X) are usually unaffected because their second X compensates, but they have a 50% chance of passing the condition to each son.

In fertility, X-linked inheritance is a key reason for PGT-M testing. Couples who know they carry an X-linked condition can use IVF with PGT-M to select unaffected embryos (either unaffected males or carrier/non-carrier females).

Genetic counseling before IVF helps couples understand their transmission risk and decide between PGT-M, prenatal testing, or other family-building options.