Male Animals Might Benefit From Infecting Their Female Partners With STDs

(Credit: Paul Reeves Photography/Shutterstock) (Inside Science) -- In the battle of the sexes, sexually transmitted diseases may sometimes be a weapon that males use to win. That’s the conclusion of a new study that used mathematics to model an age-old evolutionary struggle: the quest to fill the next generation with as many of your offspring as possible. The findings probably don't apply to humans, and the outcome would vary depending on the animals and diseases involved, said the researchers. But by infecting a female with an STD, a male animal may be able to prompt his mate to invest more energy and resources in his own babies, rather than in future babies with other males. The study was conducted by researchers at Australian National University in Canberra, including evolutionary biologist Megan Head and then-graduate students Sophie Johns and Jonathan Henshaw. "There's a kind of tendency to think that [STDs] are just bad things that individuals should always want to avoid," said Henshaw. But, he said, from the perspective of a male animal, "there can be situations where [STDs] have beneficial effects."