Donating bone marrow does not shorten your life.
When you donate bone marrow the bone marrow that was removed from you for donation will eventually grow back on it's own.
So you will get the bone marrow back naturally when you donate your bone marrow.
So you'll still have new bone marrow growing in place of the old donated bone marrow.
It's a myth that your life will be shorted when donating bone marrow.
Many people who donate bone marrow go on to live a normal life expectancy.
It's worth it to donate bone marrow to save lives.