Although press and television reports on women at the military academies, in basic training and boot camps, on ships and in Air Force blue may suggest the dawning of an age of American Amazons, the image is far from the reality.

Despite a doubling in their numbers in the armed forces since the end of the Vietnam war, women still make up only 5 per cent of military personnel due to restrictions that could sorely inflate the Defense budget, reduce the size of the armed forces, or lead to reinstatement of the draft, according to a report by the Brookings Institution.

While stopping short of calling for combat roles for women, the authors of the report - civilian defense analyst Martin Binkin and Air Force Lt. Col. Shirley J. Bach - urged the armed forces to move toward less restrictive personnel policies that could triple the Pentagon's projected increase in women in the services by 1982.

As it now stands, the armed services expect to increase the number of women in their ranks from 108,000 today to 147,000 by 1982, so that women would make up 7 per cent of the forces.

But the Brookings report found that even excluding women from frontline combat jobs, the services could enlist 400,000 women, or 22 per cent of the total, at the conservative estimate. Fully a third - over half a million women - might be enlisted, a move that would make three-quarters of Air Force personnel and one-quarter of the Army female.

Full equality - combat duty - for women in the military should await studies of the impact of their presence on group morale, the study's authors said.

The women's movement has played a part in the push toward greater participation by women in the military, but the authors said the economics and politics of the volunteer services may prove the crucial factor in the next decade or two.

The sudden deflation of the baby boom in the 1960s means that by 1985 the pool of 18-year-old male high school graduates will be markedly reduced. Women could expand that pool.

The alternatives to overcoming the dwindling pool eligibles could lie in reducing the size of the armed forces (and hence, in theory, the country's military preparedness), increasing military pay - the largest single factor in the defense budget - to competitive levels with the civilian market, or in bringing back the draft.

Even if the revival of the draft in peace time proved politically palatable, they said, the draft would inevitably have to include women.

The authors noted the problems of manpower (even with the draft, there would not be enough males to fill the needs of the services, so that the women would also have to answer the call.

Moreover, women as soldiers have proven less expensive than men, and have a rate of lost time for illness and absenteeism half that of men (including time lost for pregnancy) making women a bargain for the military and the taxpayers.

The Brookings report recommended experimental studies by the Pentagon to determine just what impact the presence of women in frontline combat units would be, including explorations of such things as the desirable ratio of men to women.

In the meantime, the military services should relax the artificial restrictions on women's roles, now maintained by sweeping definitions of what combat duty entails.

Air Force classifications of combat aircraft keep women from working on maintenance crews of planes and out of jobs on missiles sites.

The Navy could allow women to work on support vessels, rather than barring women completely from sea duty

The Marines' ability to open their ranks to women is curtailed by both the Navy restriction on sea duty and the Army's on combat duty.

Such moves - along with the experimental studies of combat units - would provide a factual basis for setting national policy, determining whether women could make a useful contribution to combat units and whether they would serve in such roles in a volunteer force.