The transmission of HIV-1 infection from men with hemophilia A to their female sex partners and secondarily to their children was studied by serological markers including antibody, antigen, and HIV genome as detected by the polymerase chain reaction (PCR). Among 27 sex partners of 26 seropositive hemophiliacs, 5 were seropositive-PCR positive (active), 11 were seronegative-PCR positive (latent), and 11 were negative for both. These results were confirmed by testing serial serum samples and paired samples of DNA from peripheral blood mononuclear cells (PBMCs) and serum from seronegative women. PCR negativity in exposed women was correlated with the use of condoms (p less than 0.01). Eight children from five couples were seronegative. However, HIV-1 infection as detected by PCR was transmitted to 60% of exposed children, including one from a seronegative-PCR positive mother.