Angelina Jolie is the latest in a string of famed women to announce she’s had risk-reducing breast surgery after discovering she carries a breast cancer (BRCA) gene. Before her, Michelle Heaton and Sharon Osbourne have also had this major surgery, which can reduce the risk of breast cancer by up to 95%. But what does surgery involve? What are the BRCA genes and how do you know whether you carry one? And while the benefits…