The main study is a single arm, open-label, prospective study to assess antiretroviral activity and tolerability of etravirine (TMC-125) 400 mg once daily, given with fixed-dose tenofovir/emtricitabine, in treatment-naïve HIV-1-infected men and women. There are also a genital secretions pharmacokinetic (PK) sub-study and a metabolic sub-study. The purpose of the genital secretions PK sub-study is to gain information about drug levels and HIV-1 RNA in genital secretions when subjects are taking etravirine. The purpose of the metabolic sub-study is to learn about the effects of etravirine on body composition, as well as lipid and glucose levels.