To get started, I did my research and came back with some interesting results. It seems the reason why many people don't register in the bone marrow donor system is because of a lack of knowledge of the process that it takes. When people think of bone marrow transplant, they think of this painful experience of your spine being extracted or something, but it's just a swab of the cheek. The actual bone marrow transplant isn't often painful either. "The majority of transplants are now done through the donation of peripheral blood stem cells - which is essentially a painless removal of these kind of cells from the donor via intravenous extraction - and not directly from the bone marrow." The issue is public's lack awareness of the truth.
If I were to come up with a main idea that an ad agency or anyone could hold onto, it would be this:
Becoming a registered member in the bone marrow registry and donating doesn't hurt.
Creative Ideas I will elaborate more on later are these:
A series of harmless scary monsters that can demonstrate that bone marrow procedures really aren't all that painful.
A series of short viral videos that demonstrate acts that hurt way more than swabbing a cheek. For example: getting slapped, punched, running into a pole, or falling off a skateboard. Thinking similar to failblog is one way of thinking about it.