A deep male voice, which typically attracts women as a sure sign of supreme manliness, can also be a sign of lower sperm count, a new study has found.
Leigh Simmons, Marianne Peters and Gillian Rhodes from the University of Western Australia say that while men with deep voices may have more testosterone, too much of it can reduce the amount of sperm it ejaculates.
The result came as a surprise because it's widely accepted that females use traits such as a deep voice, hairiness and muscle size as a way of sensing a man's virility, which is the same in the animal kingdom.
The investigation began by establishing that women did indeed find a deep voice an attractive quality in a man, after listening to the voice recordings of 54 men aged between 18 and 32.
Those men were also asked to provide a sperm samples.
After noting that lower sperm counts were associated with the men with deeper voices, the researchers concluded that perhaps some sort of trade-off was taking place.
They believe it could be nature's way of balancing things out, so that if one has the voice and muscles women love so much, they lose out on the virility front.
However, all the sperm counts measured were within healthy parameters.
The study has been published in the journal PLos ONE.