Number of sexual partners and age at first intercourse in subsequent generations of Italian males and females.

Trends in the number of sexual partners and in age at first intercourse were analyzed using data on 706 men and 1206 women drawn from the hospital control groups of two case-control studies conducted since 1981 in Northern Italy. The overall lifelong mean number of sexual partners was 7.5 +/- 12.8 for men and 1.4 +/- 1.8 for females. The mean number of sexual partners was 6.0 for men born between 1910 and 1919, and 7.3, 9.0, 6.3 and 5.5 for subsequent 10 year birth cohorts. Mean age at first intercourse was 20.7 for the cohort born in 1910-19 and was fairly stable in men born after 1919, ranging from 18.4 to 18.8. Women had a substantially lower number of sexual partners than men in each subsequent birth cohort. However, the mean number of sexual partners increased from 1.1 in the 1910-19 cohort to 1.2, 1.2, 1.4 and 2.3 in subsequent birth cohorts, and the mean age at first intercourse decreased from 23.6 years to 23.1, 22.7, 21.3 and 19.7. These figures should be considered with caution, on account of the non-representativeness of the sample and of a possible under-reporting of number of partners by women. Still, Italian women, although not necessarily men, report substantially fewer sexual partners than northern European on American ones.