Ex-England footballer Emile Heskey has started giving blood after discovering two of his children have the sickle cell trait gene.
Carriers of the gene are at risk of having children born with sickle cell disease, which afflicts mainly people with Afro-Caribbean heritage.
Sickle cell disease means red blood cells are sickle shaped rather than circular. This leads to painful blockages that damage major organs and can culminate in a fatal stroke.
