Sexism has been rampant for decades in Silicon Valley, where the uphill battled faced by women in technology is becoming more widely known through a number of books and articles. Emily Chang, a television journalist with Bloomberg News, is adding to the narrative with her new book, Brotopia: Breaking Up the Boys’ Club of Silicon Valley . Chang exposes stories of  eye-popping sexism in the industry while also revealing a surprising fact: Silicon Valley wasn’t always so dominated by men. She discussed her recent book on the  Knowledge at Wharton show,  which airs on SiriusXM channel 111 . An edited transcript of the conversation follows. Knowledge at Wharton: The male-centric culture of Silicon Valley is not a hidden story, yet you bring out some amazing details in this book that capture attention. Are people wondering why this environment persists there? Emily Chang: When I started doing my research, I thought this is how the tech industry always was.…