U.S. District Court Judge Gerhard A. Gessell ruled yesterday that a 31-year-old policy of the Veterans Administration to appoint only veterans to the Board of Veterans Appeal discriminates against women and is therefore illegal.

The policy was first instituted at the end of the Word War II in 1945, when Gen. Omar Bradley, who was then the administrator of veterans affairs, recommended to President Harry S. Truman that only veterans - and preferably only wartime veterans - should be named to the board because of the nature of the panel's work.

The 50-member board conducts hearings and disposes of appellate claims involving veterans' benefits, and consists of smaller panels that each include one physician and two attorneys. From 1945 to 1975, only three of the 121 board members appointed were women.

The members of the board, who are paid at minimum rate of GS-15, or $33,789 annually, are chosen from among staff attorneys and medical advisers on the staff of the VA.

A suit on behalf of all non-veteran staff female attoneys and physicians challenged the policy as violating the Civil Rights Act because so many more men are veterans than are women. Statistics presented to Gesell showed that 40 per cent of male attorneys and physicians are wartime veterans while less than 1 per cent of such female professionals are similarly situated, the judge said in his opinion.

"It places female attoneys and female physicians at a marked disadvantage in seeking consideration for appointment to the board and has caused the board to be composed almost entirely of men," Gesell said of the veterans-only policy.

Veterans group and the VA argued that since the board's decisions affect only veterans, there is a strong need that the members of the panel also be veterans.