Dr. Anupam B. Jena of Massachusetts General Hospital in Boston led the study that researched the sexual practices of older men taking drugs like Viagra and Cialis. While younger people have more partners and more STDs, it appears the rate of infection in older adults is rising because those over 50 are six times less likely to use protection.

“We are typically unaccustomed to practice safe sex over the age of 50, because the risk of pregnancy is eliminated,” Dr. Jena told Reuters Health.

In other studies, researchers have found there may be a biological function of pining for lost love. When looking at photos of lost partners, male and female subjects exhibited activity in the regions of the brain associated with rewards, control of emotions and addiction cravings.

“Romantic love is an addiction,” notes study author Helen E. Fisher, a biological anthropologist at Rutgers University. “It’s a very powerfully wonderful addiction when things are going well, and a perfectly horrible addiction when things are going poorly.”

Gee, wasn’t there a song about that?