Blood cancer doesn’t pick people based on where they’re from. It doesn’t care about ancestry, background, or postcode. But the system that treats it does depend on those things, because finding a stem cell donor comes down to genetics. And your genetics come from who you come from. That’s why diversity matters, and why understanding the gap starts with how matching works.
For some people who need a transplant, there are hundreds of potential donors on the registry. For others, there are almost none. The difference between those two outcomes isn’t luck. It’s whether enough people from a similar background have signed up.
How stem cell matching actually works
A stem cell match isn’t about blood type. It’s about tissue type.
Markers called human leukocyte antigens, or HLAs, sit on the surface of your cells and act like ID tags for your immune system. They help your body tell the difference between what belongs and what doesn’t. When someone needs a transplant from a donor, doctors look for someone whose HLA markers line up as closely as possible with the patient’s. The closer the match, the lower the risk of complications and the better the chance the transplant works.
There are thousands of possible HLA combinations. Even siblings only have about a one in four chance of being a perfect match. That’s why unrelated donors matter so much, and why the registry needs to be both large and diverse. You can read more about how donors are matched on our matching page.
Why diversity matters when you need a match
Aadil making stem cell donation look easy
You inherit your HLA markers from your parents, so your ancestry directly shapes your tissue type. Because of that, people are more likely to match with someone who shares a similar ethnic background. This isn’t about identity in a social sense. It’s about genetics.
Some communities are well represented on the Australian stem cell donor registry. Others aren’t. When fewer people from a particular background have signed up, the chances of finding a match for someone from that background drop significantly. Someone with Northern European heritage might have dozens of potential donors. Someone with mixed heritage or from a smaller community might have very few.
It’s not because people don’t care. It’s simply because not enough people from those backgrounds have joined yet.
Around 185,000 people are on the Australian registry, and Stem Cell Donors Australia manages and types it carefully. The numbers work for Australia overall. But the registry doesn’t yet reflect the mix of people who actually live here. As a result, Australian transplant teams source more than 80 percent of their stem cells from overseas donors. International registries help every day. However, if someone’s tissue type is rare and their background isn’t well represented anywhere in the world, finding a match can still be incredibly difficult. That’s the gap diversity on the registry is trying to close.
The challenge facing First Nations Australians
For most underrepresented communities, more registrations would make a real difference. For Aboriginal and Torres Strait Islander peoples, the challenge goes further.
First Nations Australians carry genetic diversity unlike any other population, shaped by tens of thousands of years of history on this continent. That means HLA types found in Aboriginal and Torres Strait Islander communities often don’t appear on overseas registries at all. For other underrepresented groups, international searches can sometimes fill the gap. For First Nations patients, that safety net largely doesn’t exist.
It’s why diversity matters most at the local level. Registrations from within these communities are the only realistic path to finding matches for First Nations Australians who need a transplant. Without them, some searches will simply have nowhere to go.
Why diversity matters for everyone on the registry
Charles donated stem cells through his blood. The whole process took five hours.
This isn’t about ticking boxes or filling quotas. It’s about making sure the system actually works for the people who need it, no matter where their family comes from. Every person who joins from an underrepresented background changes the odds for someone in their community.
How you can help
If you’re aged 18 to 35 and in good health, you can join the Australian stem cell donor registry. Signing up takes a few minutes online, and you’ll receive a cheek swab kit in the post. Once you send it back, the registry adds your tissue type and makes it searchable worldwide. Then you just get on with your life.
Most people who join will never be called. But if you are, it means you’re a potential match for someone who needs you. Aadil, a TLR donor of Sri Lankan heritage, described his experience donating stem cells to a complete stranger. The more people who sign up from all backgrounds, the more lives the registry can reach.
Sign up through the TLR Foundation’s partner page.
Be a legend. Save a life.
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