Sexual transmission of hep C among heterosexuals is rare (it's mostly transmitted through needle sharing), but repeated studies have shown that men who have sex with men are at risk of infection through sex. HIV-positive men, in particular those with lower CD4 counts and those who engage in unprotected receptive anal intercourse, are at significantly higher risk. Research from the University of California at Los Angeles suggests that such transmission of hep C dates as far back as the early 1980s. Another study of patients at Fenway Health in Boston found that 1.6 percent of its study population of more than 1,100 HIV-positive gay men became infected with hep C each year, which researchers attributed mostly to sexual transmission and non-injection drug use. (Shared cocaine straws may transmit the virus between nasal passages.) The Fenway study authors recommend that HIV-positive gay men test routinely for hep C and that health care providers give risk-reduction counseling to those who use recreational drugs or engage in unprotected sex.