According to the researches made on the functionality, it has been found that the productivity of male nurses is more than female nurses in making deliveries, that is resulting in more pay to them.

In the study published Tuesday, researchers looked at data from the National Sample Survey of Registered Nurses, which ended in 2008, and the Census Bureau’s American Community Survey 2001-2013. After controlling for age, race, marital status, and number of children at home, they found that males out-earned females by almost $7,700 per year in outpatient settings and close to $3,900 in hospitals. The biggest pay gap was for nurse anesthetists, with men making $17,290 more.

Ulrike Muench, the study’s lead author and an assistant professor of nursing at the University of California, San Francisco, told NPR the researchers are not entirely sure why there is such pay disparity. Some experts suggest that men are more likely to negotiate for a higher salary, others say that men work more on nights and weekends, when the pay can be better, and still others believe it comes down to gender discrimination. Whatever the reason, it’s “dismaying,” says Peter McMenamin, health economist at the American Nurses Association. “We would like any differentials in pay to be based on skills and experience and not on gender.” Catherine Garcia