Study: STDs are more likely to discourage the evolution of monogamy than encourage it

According to a new mathematical study, the presence of sexually transmitted pathogens is often more likely to dissuade the evolution of monogamy than encourage it. Sure, individuals who go condom-free with a long-term partner are safer from diseases such as Chlamydia and gonorrhea than those who ditch the protection with a series of one-night stands. But over generations, STIs encourage monogamy only if they are moderately transmissible and fatal.

“Certainly, if everyone in the population just decided at a certain time they were all going to pair up and stick to this strategy, you could have a pathogen eradicated,” said study researcher David McLeod, a doctoral student at Queen’s University in Ontario. “What happens in nature is most of these behaviors are rare initially, so whether or not they succeed or fail is determined [at a time] when they are rare.”