Are you a man or are you a mouse? - The answer is both if you're being used for Alzheimer's research.
New research has found that Alzheimer's and dementia research is being conducted on male mice only, despite women making up a larger proportion of those diagnosed with the disease.
The research was presented at Alzheimer's Disease International's recent annual conference.
Speaking at the conference in Chicago last week, the Women's Brain Project argued that like the human brain, there are differences between the sexes and this could be pivotal in making advancements or curing alzheimer's disease.
Gender does play a role in the risk of developing and being diagnosed with dementia, said Alzheimer's New Zealand chief executive Catherine Hall.
"The number of women with dementia is around 30 percent higher than men and women also deteriorate quicker than men do, so it's essential that research looks at gender difference if we have any hope of tackling this serious problem," she said.
Ms Hall says currently around 60,000 New Zealanders have dementia and that number is expected to triple by 2050.
But this problem isn't isolated to Alzheimer's and dementia research, but medical research as a whole.
University of Auckland microbiologist, Siouxsie Wiles said bias is a factor in science.
"One of the reasons was there was a worry the estrus cycle of female animals would influence the results, it would make things harder to standardise because they have a cycle, but so do women," she said.
Dr Wiles said she personally tends to use female mice because they're less aggressive towards each other, but using only one gender for research can skew the science.
"A few of the studies I found [on gender bias] suggested there was one around pain and drugs had made it all the way to human trials, but when they went back and looked at it on male and female mice, there were differences in the way those drugs worked and were more likely to work on the male mice."
She said it would be wise to consciously choose before research is conducted whether the tests should be done on female and male animals or cells.
However, she added this would double the cost of tests and in countries like New Zealand it's already difficult to get research funded.