Over the last 40 years there has been a substantial increase in the share of women in national security-related positions but there is room for much more, especially at senior levels, a report has said.

A study by the Center for a New American Security dates the shift from roughly the time that women were accepted into the military academies, saying the impact has spilled over into both the private sector and governmental security sectors–in the latter case, DoD, DHS, CIA and others.

Women’s representation as a percentage of the workforce has grown consistently at the CIA, from 35 percent in 1980 to 46 percent in 2012, for example, although it’s only 31 percent in senior positions and even that number is much higher than in other intelligence agencies, it said.

“The presence of women at the top–however limited– is a promising indication that there is a pathway for mobility. It also indicates a cultural acceptance of women in leadership positions–which has not always been the case within the national security community. But the low numbers of women in leadership positions, particularly given the growing number of women graduating from elite national security and policy programs, point to structural issues within the human capital pipeline of women in national security, whether at the moment of recruitment or related to retention. It could be that too few women are entering the national security sector, or perhaps they are not staying long enough to reach the top,” it said.

One barrier on the front end, it said, is that the veterans preference policy in federal hiring “may unintentionally skew opportunities away from women” because the large majority of those who serve in the military–around four-fifths–are male. The relative lack of work-life flexibility due to the nature of the work hampers retention, it added.

It said that the government’s national security sector “can follow the lead of corporate America in finding workforce management practices such as job sharing and scheduling flexibility, which can mitigate retention issues–particularly for parents, though certainly not limited to them.”

Such policies benefit men as well as women, it said, adding that “the creation of policies that enable more women to succeed in the national security sector does not mean that the national security sector is a zero-sum game in which women can only succeed at the expense of men.”