‘Macho’ Men May Have Less Sperm

High testosterone levels may be associated with a deeper voice, more masculine features, more dominant behavior and more success with women, but new data suggests it may have little to do with virility.

In a study published last month in the journal PLoS ONE, researchers at the University of Western Australia who compared male voice pitch, women’s perceptions of it, and semen quality found men with deeper voices actually had less sperm concentration in their ejaculate. They also discovered that while testosterone plays an important role in the formation of sperm, high levels of it can actually impair sperm production.

Their findings are a bit of a surprise, since it’s believed that females of all species glean information about male virility through secondary sexual traits. In humans this includes facial hair, muscle mass and — yes — deep voices, while animals like birds look to other signs such as colorful plumage when choosing a potential mate.

So if you’re a guy without a booming voice or six-pack abs, take heart. It seems there’s a trade-off — traits associated with dominance and attractiveness may come at the cost of reduced sperm quality.