Donating or giving bone marrow is not really dangerous and is relatively safe for the bone marrow donator.
The only real risk with donating bone marrow is the use of anesthesia and it's effects on some people but even that is pretty safe.
Most bone marrow surgeries to donate bone marrow go through without any problems.
But you might feel sore for a few days where the bone marrow was removed from.
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.