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Gender agenda: sex bias can be justified in animal research

Concern over gender bias in human clinical medicine is a separate issue from male bias in animal research (Nature 465, 665 2010 and Nature 465, 688–690 2010)

Justifications for using a particular sex in animal studies include intrinsic biological variation (for example, male aggressiveness, female hormonal cycling, disproportionate disease effect on one sex in some disease models) and practical considerations (such as preference for less-aggressive females that can be group-housed to save money). Single-sex animal experiments will continue as long as research budgets are limited.

Best-practice standards for regulatory agencies and industry already require that both sexes be investigated in animal studies used for translational medicine, drug development and pesticide registration (see Although these animal data are indispensable for risk assessment for humans, they cannot reliably predict gender-specific responses in humans because of the physiological differences between species. Human data are needed before regulatory changes can be made to improve gender balance in human clinical trials.

To improve the quality and utility of animal-research data, any new mandate from journals and funding bodies on the conduct and reporting of animal studies should insist on full experimental details. In addition to gender balance, these would include key information for study interpretation, such as the animals' source, age, strain or stock, husbandry conditions and health status.

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Bolon, B. Gender agenda: sex bias can be justified in animal research. Nature 466, 28 (2010).

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