Context The current public debate regarding whether oral sex constitutes having had sex or sexual relations has reflected a lack of empirical data on how Americans as a population define these terms.

Objective To determine which interactions individuals would consider as having had sex.

Methods A question was included in a survey conducted in 1991 that explored sexual behaviors and attitudes among a random stratified sample of 599 students representative of the undergraduate population of a state university in the Midwest.

Participants The participants originated from 29 states, including all 4 US Census Bureau geographic regions.

Approximately 79% classified themselves as politically moderate to conservative.

Main Outcome Measure Percentage of respondents who believed the interaction described constituted having had sex.

Results Individual attitudes varied regarding behaviors defined as having « had sex. : 59% (95% confidence interval, 54% - 63%) of respondents indicated that oral-genital contact did not constitute having »had sex with a partner.

Nineteen percent responded similarly regarding penile-anal intercourse.

Conclusions The findings support the view that Americans hold widely divergent opinions about what behaviors do and do not constitute having had sex.