Reinisch J M, Hill C A, Sanders S A, Ziemba-Davis M
Kinsey Institute for Research in Sex, Gender, and Reproduction, Indiana University, Bloomington, USA.
Fam Plann Perspect. 1995 Mar-Apr;27(2):79-82.
According to a 1991 study of sexual behavior based on a random sample of heterosexual undergraduates at a Midwestern university, 80% of the males and 73% of the females had experienced vaginal or anal intercourse. The average age at first vaginal intercourse was 17.2 years for both sexes. Seventeen percent of the sexually experienced males and 18% of the sexually experienced females had engaged in heterosexual anal intercourse; among these respondents, the average age at first anal intercourse was 20.3 for males and 19.1 for females. Although less than four years, on average, had elapsed since the respondents had first had vaginal intercourse, males reported an average of 8.0 lifetime vaginal-sex partners and females reported an average of 6.1. Overall, the findings from this random sample of students are similar to those from a 1988 convenience sample of the same college population.
根据1991年一项针对美国中西部一所大学的异性恋本科生随机样本进行的性行为研究，80%的男性和73%的女性有过阴道性交或肛交经历。两性首次阴道性交的平均年龄均为17.2岁。有性经历的男性中有17%、女性中有18%进行过异性肛交；在这些受访者中，男性首次肛交的平均年龄为20.3岁，女性为19.1岁。尽管受访者首次进行阴道性交平均还不到四年，但男性报告的终身阴道性伴侣平均为8.0个，女性为6.1个。总体而言，从这个学生随机样本中得出的结果与19
