Many factors are thought to play a role in getting Graves' disease. These might include: Genes. Some people are prone to Graves' disease because of their genes. Researchers are working to find the gene or genes involved. Gender. Sex hormones might play a role, and might explain why Graves' disease affects more women than men. Stress. Severe emotional stress or trauma might trigger the onset of Graves' disease in people who are prone to getting it. Pregnancy. Pregnancy affects the thyroid. As many as 30 percent of young women who get Graves' disease have been pregnant in the 12 months prior to the onset of symptoms. This suggests that pregnancy might trigger Graves' disease in some women. Infection. Infection might play a role in the onset of Graves' disease, but no studies have shown infection to directly cause Graves' disease. Graves disease is an autoimmune disorder that leads to overactivity of the thyroid gland (hyperthyroidism). The ...