The Center for Disease Control and Prevention (CDC) in the US just released a report ¹ summarizing their own health statistics collected from 2006-2008 regarding sexual behavior. When we read the results, we decided that we had to write this addendum to our post about people’s perception of the average number of sex partners. Many of our numbers in this article came from a comprehensive report published in 1994, which did cause us to wonder whether or not things have change in the last decade and half. The answer is, basically, no.

According to the CDC’s report, which surveyed 13,495 15-44 year olds, 75% of women and 69% of men reported zero or one sex partner (of the opposite sex) in the past 12 months. Only 3% of women and 6% of men reported more than three. They were also asked about their total lifetime partners. The CDC reported median (or 50th percentile, meaning half were above and half were below) partners instead of average, which is more appropriate than average in this case for a number of statistical reasons (a floor effect coupled with many high outliers, for those of you who are interested). The median number of partners for men was five, and the median for women was three.

Now some of our more observant readers may be thinking to themselves right now: “Wait a minute, they said 15-44 year olds. Fifteen year olds are bound to have fewer partners than 44 year olds, so if you bunch them all together, you will get a number that’s too low.” This is good thinking (you’re really thinking like a scientist if you said this), but you would only be half right. Yes, the younger members of the group had fewer total partners. The 15-19 year olds in the group reported a median of 2 for men and 1 for women. However, when you look at the age group with the most partners, it is mot much different from the overall median for everyone. Among men, every age group over 25 pretty much had a median of 6. For the women, most age groups over 25 had a mean of 4. The likely reason for this phenomenon is the fact (which we discussed in the original article) that most people end up pairing off at some point in their lives.

It was interesting to see this new data, and how well it lined up with prior surveys. Also interesting was the consistent difference between the numbers reported by men, and those reported by women. Considering that the data only took into account opposite-sex partners, you would expect the numbers to be the same. As it turns out, this difference is consistent across most surveys of sexual activity… but that is a larger topic, and one which we plan to cover in a future installment of the blog.

Interested in these findings? Read the original post.

1. Chandra, A., Mosher, W. D. , & Copen, C. (2011). Sexual behavior, sexual attraction, and sexual identity in the United States: Data from the 2006–2008 National Survey of Family Growth (National Health Statistics Report No. 36). Retrieved from Centers for Disease Control and Prevention website: http://www.cdc.gov/nchs/data/nhsr/nhsr036.pdf