The Swiss government issues an official judgment that says what few AIDS groups in the US dare admit:
During effective ART [anti-retroviral therapy], free virus is absent from blood and genital secretions. Epidemiologic and biologic data indicate that during such treatment, there is no relevant risk of transmission. Residual risk cannot be scientifically excluded, but is, in the judgment of the commission, negligibly small.
More here. They support responsible, careful negotiated sero-sorting as a means of HIV-prevention. Gay men have figured that out already, of course. It's just AIDS Inc that hasn't.