An important topic among academics and industry practitioners is how sex has been used in advertising. To contribute to this conversation, Advertising & Society Quarterly assembled a group of leading advertising practitioners, scholars, and activists at Duke University's Hartman Center for Sales, Advertising, and Marketing History for a roundtable on sex in advertising. Part I of the Roundtable on Sex in Advertising covers the history of sex in advertising, the reasons why sex has been used in advertising, how sex has been used in advertising, men's and women's different treatments in advertisements involving sex, and the relationship between the concepts of gender and sex in advertising.