Question

If a haemophilic father (Xh Y) has children with a normal mother (XH XH), what will be the status of all sons?

Options

• All sons will be carriers

• 50% of sons will be affected

• All sons will be affected

• All sons will be normal

Answer 1

A haemophilic father (Xh Y) passes his Y chromosome to all his sons, not his X chromosome. Since the mother is normal (XH XH) and passes her normal X chromosome (XH) to all sons, all sons will have the genotype XH Y, making them normal. Sons cannot inherit X-linked traits from their fathers.