High-heeled shoes often are blamed for causing bunions. But heredity is a more likely cause. For about 65 percent of people with bunions, they run in the family and can even develop at a young age. About 7 percent of people ages 12 to 14 have a bunion. Biomechanical problems, such as having flat feet, tight muscles, or reduced range of motion in the ankle, can also lead to bunions. High heels are not completely off the hook. Bunions can be made worse by ill-fitting or high-heeled shoes.