Female co-authorship increases the likelihood that a medical-research paper will address gender-related differences in disease or treatment outcomes, a study in Nature Human Behaviour finds (M. W. Nielsen et al. Nature Hum. Behav. 1, 791–796; 2017). Neglecting these disparities — which affect health outcomes in conditions such as cardiovascular disease and osteoporosis — can have life-threatening consequences, the study adds. The authors analysed more than 1.5 million medical-research papers published between 2008 and 2015. They found that the research was most likely to address gender differences when female scientists were first and last authors. However, female researchers comprised only 40% of first authors and 27% of last authors in the papers analysed. This is troubling, the study authors say, because last authors usually lead on identifying, planning and developing research pursuits in health disciplines. Increasing numbers of medical researchers, journal editors and science agencies already acknowledge the importance of including gender analysis in research, the authors note.