For most U.S. adults, sex is not something one makes an appointment for -- rather, it occurs spontaneously for the vast majority, a survey indicates. Eli Lilly and Co. sponsored the online poll, conducted by SKIM Healthcare, which collected information on sexual behavior among men and women ages 34 years and older from 13 countries -- Austria, Belgium, Canada, Czech Republic, Denmark, Finland, Mexico, Portugal, Romania, South Korea, Switzerland, the United Kingdom and the United States. In the United States, 76 percent said they do not plan ahead for sex, compared to the global average of 86 percent. Seventy-one percent of those ages 34-45 said they do not plan for sex, while 79 percent of those ages 46-60 and 77 percent of those age 60 and older said they have spontaneous sex. North Americans led the poll with 38 percent of U.S. male respondents and 22 percent of female respondents saying they have discussed sexual health and performance issues with their doctors. Thirty-seven percent of Mexican male respondents and 38 percent of female respondents, and 35 percent of Canadian male respondents and 27 percent of female respondents, said they had discussed the matters with their doctors. One-third of respondents indicated they used the Internet as a source of sexual health information. Twelve 12 percent preferred books, 11 percent said magazines and 10 percent said doctors were their go-to sources. The survey was conducted online by SKIM Healthcare on behalf of Eli Lilly and Company among 13,063 people age 34 and over -- 60 percent men and 40 percent women.