Olivia Culpo, Julianne Hough and more stars have become fierce advocates for women's health - especially when it comes to endometriosis. Endometriosis causes abnormal tissue growth in and around the uterus, and is one of the leading causes of infertility in women. The condition occurs in as many as 1 in 10 women, according to UCLA Health, and can take years before being confirmed, leading many women to not be diagnosed until their 30s or 40s. Despite the stigma, women like Culpo and Hough aren't afraid to speak up about their symptoms.