An appealing voice is a turn-on for many. But now there is strong evidence that an "attractive" voice serves a purpose: to draw people to the most genetically fit potential mates.

In a recent study, researchers showed that the human voice is an indicator of desirable yet difficult to perceive physiological and mental strengths.

Scientists measured the hands, elbows, wrists and fingers of 76 men and women between the ages of 18 to 34 to take stock of their "bilateral body symmetry." Research has already demonstrated that those with more symmetrical bodies are often more fertile, less susceptible to illness and less likely to carry genetic anomalies.

The volunteers were asked to count from one to 10 into a voice recorder, and over 100 undergraduates listened to the recordings and rated the voices on a scale from 1 to 7. The people with greater "bilateral body symmetry" also had the highest-rated voices.