Depends on type
More than 30 genes have been identified causing different types of md.
3 types of inheritance: x-linked recessive-mothers are carriers thus sons have 50% chance of developing md. Daughters have 50% chance of being a carrier. Autosomal recessive-both parents must carry & pass on md gene. Kids will have 25% chance of developing md. Autosomal dominant-each child of affected parent has 50% chance.