To the Editor: The essentially equal incidence of AIDS among male and female heterosexual Africans has continued to be an enigma when compared with the incidence in the United States, where acquisition of the disorder by heterosexual men from infected women is still uncommon (although increasing). Tattooing, scarification, the reuse of infected needles, a greater prevalence of prostitution, and the use of anal intercourse as an inexpensive contraceptive measure have all been proposed to account for this disparity.I would like to offer still another possibility — one that can also further elucidate the common media statement that AIDS is . . .