Sex differences in allometry for phenotypic traits in mice indicate that females are not scaled males

Sex differences in the lifetime risk and expression of disease are well-known. Preclinical research targeted at improving treatment, increasing health span, and reducing the financial burden of health care, has mostly been conducted on male animals and cells. The extent to which sex differences in phenotypic traits are explained by sex differences in body weight remains unclear. We quantify sex differences in the allometric relationship between trait value and body weight for 363 phenotypic traits in male and female mice, recorded in >2 million measurements from the International Mouse Phenotyping Consortium. We find sex differences in allometric parameters (slope, intercept, residual SD) are common (73% traits). Body weight differences do not explain all sex differences in trait values but scaling by weight may be useful for some traits. Our results show sex differences in phenotypic traits are trait-specific, promoting case-specific approaches to drug dosage scaled by body weight in mice. Research aimed at improving healthcare has largely focused on male animals and cells. Here, the authors use data from the International Mouse Phenotyping Consortium to show that body weight does not account for all phenotypic differences between male and female mice, supporting more female-focused research.

Automated summary

Sex differences play a significant role in the risk and expression of diseases, but previous research has mainly focused on male animals and cells. Using data from the International Mouse Phenotyping Consortium, this study reveals that body weight does not account for all phenotypic differences between male and female mice, highlighting the need for more female-focused research.