Photo: Steph Tsimbourlas endured years of pain before even hearing about endometriosis. (Supplied) A coalition of women's health groups want all teenagers to be taught about menstrual health in schools to raise awareness about the potentially debilitating condition endometriosis. As many as one in 10 Australian women have endometriosis, where tissue similar to the lining of the uterus occurs in the pelvis and other parts of the body. It can cause severe, debilitating pain and symptoms including fatigue, abnormal periods, infertility and nausea. Steph Tsimbourlas, 25, endured years of pain before even hearing about endometriosis. "I was experiencing symptoms that were specific to endo. Pain, painful periods, pain when having sex and feeling tired," she said. Despite her symptoms, she was misdiagnosed by doctors for five years, until a laparoscopic surgery diagnosed her endometriosis in 2015. "I was experiencing all the symptoms, yet according to my doctors, there were a million other things that it could have been before it was endo. 'You have scar tissue, you have cysts, do this ultrasound, do that'." 'Education is the way forward' Along with other classmates, Steph said she missed lots of school because of period pain. But she said she was never taught about endometriosis at school. "In Year 12 PDHPE [health and physical education], we learned about periods but mainly regarding bloating and PMS," she said. "I never ever heard about it then. I would have mentioned it [my symptoms] earlier. "I wish I'd been told in high school that painful periods aren't normal." About 20 per cent of teenage girls in Australia miss school because of period pain, according to Dr Susan Evans from the Pelvic Pain Foundation. "Education is the way forward to avoid future generations of girls and women suffering as their mothers have," Dr Evans said. The coalition is made up of patient groups such as EndoActive, the Pelvic Pain Foundation, as well as medical research groups such as the Hudson Institute of Medical Research and the Universities of Adelaide, Melbourne and NSW. The health groups want endometriosis to be designated as a national health priority area. They also want a