The public's perceived susceptibility to health risks does not always
accurately reflect the epidemiological estimates of actual risk. We as
sessed whether this discrepancy exists for HN infection by outlining a
nd comparing the actual statistical probabilities of acquiring HN and
another sexually transmitted disease (chlamydia) with the perceived pr
obabilities of acquiring these diseases for heterosexuals who do not u
se intravenous drugs. Our analysis of heterosexual college students' p
erceived probabilities revealed that they do not distinguish between c
hlamydia and HN infection: Their predictions are accurate estimates of
the probability of chlamydial infection but overestimates of the prob
ability of HIV infection. We also found no relationship between the fr
equency of participants' risk-reducing behaviors and their perceived p
robability of HIV infection.