When it comes to publishing medical papers, the glass ceiling is still a barrier to women being listed as first author.

New research shows that in the world’s top medical journals, female co-authors are far less likely to have their name appear first than male counterparts, despite having contributed equally to the research.

The analysis examined bylines for papers that had two authors who contributed equally to the work and shared co-first author status. Dr Erin Aakhus, a haematologist at the University of Pennsylvania found 862 research papers with co-first authors of differing genders,  published in the ten highest impact medical and science journals between 2005-14.

Males and females were equally likely to have their names listed first in by-lines for articles in high impact science journals such as  Nature .

But this was not the case for clinical journals, where women’s names appeared first in just over one in three papers (37%)  where they shared joint authorship with a male.

Female names went first in just 22% of co-written articles published in the Lancet, 24% in JAMA, 38% in the Annals of Internal Medicine and 43% in the NEJM.

The only medical journal where parity was observed was the BMJ, in which eight out of 15 (53%) of papers listed the female co-author first.

The findings raised concern because the first author position may carry the most prestige and be important for hiring and promotion, said Dr Aakhus in a research letter published in JAMA this month.

“This study suggest the need fort investigation of what factors influence byline position among co-first authors and what professional consequences, if any, result from differences in byline position of equally contributing co-first authors,”   her article concluded.