A Vancouver father was able to step in when his toddler was diagnosed with leukemia, but her case is encouraging her parents to speak out about a need for registered donors.

About nine months ago, little Aubrey Hirsch underwent a critical medical procedure in her fight with acute myeloid leukemia.

The two-year-old is thriving now, but the usually perky girl was sick with a worsening fever when she was diagnosed last year. When she arrived at BC Children's Hospital, her parents didn't think it was anything serious.

"I went into the ER kind of thinking we would maybe just get a little IV fluid to give her some electrolytes or something just to perk her up, not thinking it was any big deal, but we didn't go home," Aubrey's mother Megan Davis said.

They went straight into the pediatric intensive care unit, and Aubrey was given a bone marrow biopsy the next day. Hours later, she was undergoing chemotherapy.

But the chemo wasn't enough, a pediatric oncologist said.

"We knew early on because of her high-risk type of leukemia disease that the best treatment for her would be a bone marrow transplant," Dr. Sylvia Cheng recalled.

So the search began for a donor, conducted through the OneMatch program which taps into a worldwide stem cell and marrow registry of potential donors.

"We learned there was a perfect match somewhere in the world, but for whatever reason, that person didn't follow through," Megan said.

Needing to act quickly, doctors opted to extract marrow from Aubrey's father, Allan, although he was only a 50 per cent match.

He said he knew there was a chance it wouldn't work out, but that the opportunity to help his daughter was incredible.

"She has her life ahead of her," he said.

Only 18 such transplants have taken place at the hospital over the last three years, but fortunately the partial match appears to be working for Aubrey.

After months of treatment and recovery, the toddler is now doing well. And she's won the hearts of hospital staff.

"She lights up our clinic every time she comes and everybody loves her," Cheng said.

There is still a chance the leukemia could come back, but her parents are optimistic.

"They're learning all the time, improving outcomes for kids like Aubrey. We're really thankful for that," Megan said.

But they know not everyone is lucky enough to have a match within their family, and they encourage others to sign up for the OneMatch program to help save lives of those in need.

"The risk associated and the time associated to do it is insignificant in terms of the help you can provide," Allan said, tearing up.

While OneMatch is in need of all types of donors, Canadian Blood Services said the need for males between 17 and 35 is particularly high.

About half of stem cell donations came from men last year, but only 20 per cent of possible donors on the stem cell and marrow registry are male. Males are more likely to be chosen as donors because they offer better patient outcomes post-transplant, CBS said.

More than 80 diseases and disorders can be treated with stem cell transplants, and only one in two are able to find a match. There are hundreds of Canadians waiting for donors.

As patients are more likely to find a match within their own ethnic group, there is also a greater need for ethnically diverse donors.

Those interested in registering with OneMatch can find out more information or apply online.