Pete McCleave is in a race against time to find a stem cell donor. He has been diagnosed with blood cancer and his only chance of survival is a stem cell transplant.
But because Pete is mixed-race, his chances of finding a stem cell match are significantly lower than many others.
If Pete were of white European heritage, he would have a 60% chance of finding a match.
For any other ethnic group, the odds are 20% at best, due to poor representation of Black and minority ethnic communities on the register.
Pete has been looking back at his family history to understand a bit more about where he comes from, in the hope that knowledge can help him target the communities who may have a similar tissue type to his - and therefore, just possibly, be the genetic twin he's looking for.
Pete has had a DNA test to ascertain just what his genetic makeup is.
The results came back that his ancestry composition is 80% northwestern European, and 20% Chinese and Southeast Asian.
Delving into his family tree to understand more about where he comes from, he's hoping he can work out where to target his campaign to find more donors.
It is a history lesson that could save his life.
His Auntie Patsy has been helping to fill in some gaps.
Pete's paternal grandmother Lucille Da Costa was from Macau.
Lucille's mother, Pete's Great grandmother, was a Chinese native, and her father, Pete's Great grandfather, was a Portuguese merchant.
For Pete, and for everybody else waiting for a stem cell match, this is a numbers game.
Just 4% of the world's population is on the stem cell register.
Pete is facing the biggest challenge of his life - not fighting cancer, but finding a match.
He is now looking at how he can target those communities which may have the same genetic heritage as him.
There are big Macanese communities now in San Francisco, and parts of Canada.
Stem cell expert and former deputy director of a clinical transplantation laboratory Dr Daniel McCloskey, explains why finding out more about one's history can be beneficial in finding a stem cell match.
He says: "Your tissue type is genetically inherited from your parents so obviously where your parents, your grandparents, your great grandparents come from, has an influence on what your tissue type is or HLA type as it's called.
"The issue is that during evolution and the development of the different ethnic groups around the world, the HLA types have evolved in a similar sort of way, so you do get HLA types which are predominantly found in particular ethnic groups.
"So your heritage could be a very important factor in finding a match donor."
But Daniel points out that nobody knows exactly what their genetic makeup is, and they could just as easily be a match for someone on the waiting list, like Pete.
He adds: "Obviously it's better to look in the predominant groups that your family history is from but anybody could be a donor and not everybody knows what their heritage is so you could be that one donor.
"It makes sense to target the ethnic groups that your heritage is from but Pete could find a donor elsewhere."
Of course, you may think you know where you come from and what your heritage is, but often unexpected lineage can appear in someone's DNA.
Pete says: "You just don't know. You often don't know who you are or where you come from."
Pete points out that sometimes a match can be found without having the same ethnic background, so the more people who sign up to become donors, the more chance there is of finding a match.
Pete, like many others , is now facing the problem of a lack of diversity on the stem cell register.
But it is a problem which is ultimately fixable. It just needs more people of every race to sign up to the stem cell register.
Pete's campaign 10,000 Donors has already registered more than 90,000 new donors and 17 people have found donor matches.
How do you donate stem cells and does it hurt?
In about 90% of the cases the stem cells are taken from the bloodstream - just like giving blood. The donation takes 3-5 hours on one or two consecutive days. No surgery is necessary, you can usually leave the clinic the same day.
Am I missing stem cells after the donation?
The body reproduces the blood stem cells within about two weeks. The procedure of donating them is comparable to a blood donation, and does not lead to a permanent loss of stem cells.
Who can donate?
If you are aged between 17 and 55 years and in general good health, then you may be able to register as a blood stem cell donor. If you register when you are 17, you will not be able to donate blood stem cells yet, but on your 18th birthday, you will automatically be activated in our database and included in the global donor searches.
There is much more information on stem cell donation on the DKMS website here.
Find out more about Peter's campaign 10,000 Donors, and how to sign up to the stem cell donor register here.