[lettie]

If you are on the bone marrow register, it doesn't necessarily mean that you will be called up to donate. The only donors I have come across have been the recipients family up to now. If none of the family match, then they use the register. They look for people with matching blood group. If you have a common blood group then I reckon it would be as rare as rocking horse manure that you would be called upon to donate (there would be more people on the register with a common group therefore more to choose from.) If you do donate bone marrow then you could probably get some time off sick though...