Though advocates for the repeal of "don't ask, don't tell" are already aware that racial minorities and women tend to be discharged under the law at a higher rate than white males, a new study shows the numbers for these groups are on the increase.

Women represented a quarter of discharges in the 1990s but now make up 39% of discharges under the law banning service by openly gay military personnel, according to the Williams Institute at University of California, Los Angeles, which released the study's findings Friday. The study compares the demographics of the 13,500 men and women who have been discharged under the law.

Though women have consistently remained at about 15% of military personnel since 1997, the percentage of women discharged under "don't ask, don't tell" has increased from 22% that year to 39% in 2009. The study also suggests that the percentage of women among all LGB service members has increased from 32% in 2000 to 41% in 2008.

Discharges of white service members have declined 61% over a decade from their high in 1998. However, while racial and ethnic minorities make up a third of the U.S. military, "don't ask, don't tell" discharges among this group have risen slightly in the same time frame.