A new study has analyzed why frequency of sexual activity has been dropping among younger people in America. In particular, this study analyzed the drops for casual sex inactivity.

Among men:

The most important factor driving the decline in casual sex among young men is the decline in drinking, which alone explains more than one third of the decline. Considered individually, the increase in computer gaming explains about one quarter of the decline in young men’s propensity to have nonrelationship sex, and the rise in parental coresidence explains a little more than 10 percent. No other mediator explains a statistically significant portion of the decline in young men’s probability of engaging in casual sex. Considered together, the mediators that explain at least some portion of the decline (employment and earnings, parental coresidence, computer gaming, and drinking) explain 57 percent of the drop in young men’s casual sexual activity.

I've been very vocal about the idea that living with parents is a massive cockblock that most people won't realize, but i was somewhat surprised to know that declining in drinking and computer gamign to be the best predictors of lack of casual sex.

As for women:

We find that about one quarter of the drop in young women’s propensity to have casual sex is attributable to a decline in their frequency of drinking alcohol. Of the various sources of the decline in sexual activity considered in this analysis, the decline in alcohol consumption is the only factor that explains a significant portion of the decline in young women’s probability of engaging in casual sex.

This study comes in line with another recent study that found that 1/3 of total sexual activity decline is due to the fact that people are having less commited relationships. As i've always said, most sex is had in the context of relationships. It also found that "trends in the formation of romantic relationships, alcohol consumption, computergaming, and earnings explain a substantial por-tion of the decline in young adult sexual activity"

When i got the time, i'll probably make a better review of these and more studies, still, these are good sources that show that many of the reasons routinely offered in this sub to explain sexual inactivity are actually scientifically sound.