br br Your chances of forming gallstones that can cause symptoms are higher if you: br br Are female. Females are twice as likely as males to have gallstones. br Are older than 55. br Are Native American or Mexican-American. br Have a family history of gallstones. br You may also be increasing your risk for gallstones if you: br br Are overweight. br Lose weight rapidly or lose weight by dieting and then gain weight back again. br Are pregnant. br Are taking estrogen (after menopause) or high-dose birth control pills. br Get very little or no exercise. br Do not eat for a period of time (fast).