Cancer is complex and affects people in different ways. So, as our researchers explore cancer and cancer treatments, where possible, we also want the research we fund to provide insights that will build a better understanding of how cancer and cancer treatments differ with the different biology found in diverse patient populations.
In laboratory research, sex is one key biological variable that may influence cancer biology, but its full role in cancer and cancer treatments is understudied. By requiring the researchers we fund to include sex in experimental design, analysis and reporting, we’re helping build evidence around the role biological sex plays in cancer.
We want to hear from you if you have any questions or comments about these requirements and their impact on your research. We also want to hear about any great examples of research already integrating sex in experimental design, both where sex does and doesn’t show a difference.
Email us for supportDesign studies that take sex into account or explain why it isn't a variable of study in this experiment.
Conduct experiments using male and female samples and record results as sex-based data.
Analyse sex-based data and the interactions between all variables.
Share detailed methods and results from all experiments, including your sample groupings and how you treated the sex variable.
All grants submitted to us following July 2023 launch of this policy must comply.
Our requirements are aligned with the Medical Research Council’s (MRC) guidance and their definitions of sex and gender, to support consistency across the UK research network.
We’ll roll out these new expectations gradually across our funding portfolio and they will continue to evolve as we gain insights from the peer review process during our upcoming grant review rounds.
There will be no retrospective application of this requirement to existing awards, but we encourage all of our researchers to consider how to incorporate these principles where practical and explore ways to make their discoveries more generalisable.
Read the MRC's definitions of sex and gender
We require male and female sexes to be used in the design of experiments described in all funding applications to us that involve animals, human and animal tissues, and cells.
All applications proposing to use these biological materials should include information about the sex of the animals to be used in experiments, as well as the sex of studied tissues and cells. If you don’t know the sex of the cells and tissues you use, you should plan to determine this as part of your research where legal and ethical.
There is no requirement to ‘balance’ or use equal numbers of the sexes, although, where possible, equal numbers will support the best statistical power to examine the sex variable.
Using the same or only modest increases in sample size, you can often convert a randomised single-sex experiment analysed by student’s t-test into an experiment including males and females with multi-factorial statistical analysis. We’ve shared resources to help you do this below.
When seeking tools and examples to help guide your new experimental design, do note planning guides may be interchangeable for in vivo and in cellulo studies. These updated experimental designs should then be incorporated into your future research proposals.
Note that this requirement does not apply to the use of immortalised cell lines.
We may still fund single-sex studies where there is strong justification in the research proposal for doing so. Such justification must be included in your application.
Cases where the use of a single sex may be appropriate include:
single sex biological mechanisms or diseases (for example, ovarian cancer)
research into the mechanisms of purely molecular interactions (for example, when investigating protein-protein interactions)
where there are acutely scarce resources (for example, human tissue samples of rare cancers)
where costs would be excessive (for example, several times higher than a single sex study)
Other reasons for conducting research in a single sex will be considered as part of the peer review process. These may include scientific, logistical or ethical considerations and should have robust justification.
In most cases female variability will not be sufficient as a justification for using only one sex. We will also not accept as a justification that prior work has been performed in only one sex or that there is a lack of evidence of sex having an effect.
We encourage you to share all research outputs – including where possible those that show negative results (ie where biological sex has no impact on findings).
This can help all researchers better understand the overall effect of different biological factors and support the development of future hypotheses and study designs.
National Institutes of Health approach to research robustness and reproducibility
SAGER guidelines on reporting of sex and gender in scientific publications
Experimental Design Assistant (EDA) for designing in vivo experiments
Draft RIVER recommendations for reporting in vitro experiments
Example exploring study size when incorporating males as well as females
Guidance on the cohort size and support for developing robust animal experiments
National Mouse Genetics Network, a community developing and sharing new mouse models
Sex and gender analysis improves science and engineering (Tannenbaum et al 2019 Nature)
The sex variable is relevant in cancer (Haupt et al 2021 Nature Reviews Cancer)
The spectrum of sex differences in cancer (Rubin 2022 Trends in Cancer)
Our strategy shapes how we'll discover more about the mechanisms of how cancer develops and progresses to unlock new and better ways to prevent, detect and treat it.
Explore the resources, policies and other support we offer to help you understand how to apply for and manage your funding.
