Women hold one in five top jobs in science, technology, maths and engineering globally, which slows down innovation, a study of research institutions said on Thursday.
While women made up more than 50% of higher education students in those subjects - known collectively as STEM - their numbers fell dramatically with seniority, found a study by the University of Michigan and the New York Stem Cell Foundation.
On average, women filled about 40% of assistant professor jobs, 30% of associate professor positions, and 20% of full professor jobs, it said.
"When women are prevented from reaching their full potential, the entire field suffers," said Susan L. Solomon, head of the New York Stem Cell Foundation, which works to accelerate cures for major diseases through research.
"We need 100% of the available brainpower to make the biggest impact and move research forward as quickly as possible," she said in a statement.
The study collected data from more than 500 academic and professional institutions to determine the hiring and retention rates of women, as well as the support systems in place, such as parental leave and development opportunities.
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Researchers examined more than 1,200 "report cards for gender equality" in nearly 40 countries over four years.
They found 38% of institutions surveyed offered additional support mechanisms for paid family leave, while 77% had no policies to support gender equity on decision-making committees.
Other results were more positive, with some having policies to address childcare, flexibility, funding and career development initiatives.
Overall, the study found that research institutions were failing to retain and promote women into positions that allowed them to carry out high-impact research.
But Solomon expressed optimism that the report cards were raising awareness of the problem.
"Simply asking institutions to fill out this report card draws their attention to the gender equity issue, encouraging them to identify areas for improvement and make necessary changes," she said.