Within a randomized , placebo-controlled trial of daily oral tenofovir disoproxil fumarate ( TDF ) and combination emtricitabine ( FTC ) / TDF PrEP for HIV-1 prevention conducted among heterosexual HIV-1-serodiscordant couples , we assessed the impact of TDF and FTC/TDF use on male fertility , measured as incident pregnancy in female partners of men assigned to PrEP vs. placebo .