If you don`t believe young women get breast cancer, you`re probably a young woman. And you`d be wrong. In fact, breast cancer is the number one cause of cancer death in young American women ages 15-54. Early detection can change that fact. So Yoplait wants every girl to pledge to get to know her girls. Know your girls. Lower your risk. Take the pledge. For every pledge, Yoplait will donate money to fund new breast cancer research benefiting young women.