A billionaire investor in a Silicon Valley venture capital firm is set to testify for a second day in a high-profile sex discrimination lawsuit that accuses the firm of being an all-boys club, where women are treated as second-class citizens. John Doerr, a partner at Kleiner Perkins Caufield & Byers, will again take the stand Wednesday in San Francisco Superior Court in the lawsuit brought by his former chief of staff, Ellen Pao, who says she was denied a promotion because she is a woman and was fired in 2012 after she complained and filed the lawsuit. The case has sparked debate over the treatment of women in the high-tech and venture capital fields. Doerr insists he tried to increase the number of women in venture capital and the technology sector, saying 'Almost always, women are better leaders than men.' Pao is seeking $16 million in damages.