Smoky, hypnotic and world-weary, Marlene Dietrich's voice had it all when it came to saying "come up and see me some time".
So too, according to a poll of the most seductive female voices, do those of Michelle Pfeiffer and Angelina Jolie. And as for the men, who could beat Leslie Phillips's classic opening line: "Well, hello..."?
A scientific study has concluded that lowering your voice is an instinctive means of demonstrating attraction to the opposite sex.
In a test, men and women were asked to phone three people after only seeing their photographs. One target was described as "attractive", one "unattractive" and one "average attractive". When they called the person rated most attractive they lowered their voices the most.
"We found that both sexes used a lower-pitched voice and showed a higher level of physiological arousal when speaking to the more attractive opposite-sex target," said the study by American psychologists from Albright College, in Pennsylvania, and the University of Baltimore. "The sound of a voice can communicate a wealth of biologically and socially important information to potential mates," the scientists said.
People with more attractive voices "reported having sex at an earlier age, more sexual partners and more infidelity than those with less attractive voices. Individuals with attractive voices are thought to be warmer, more likeable, honest, dominant and more likely to achieve".
The test involved 20 male and 25 female students from Albright College - and the tone of voice was backed up by "galvanic skin response", a test where electrodes measured physiological changes in the skin.
"Callers showed greater change in skin conductance when speaking to the attractive target," said the report.
The scientists also claim women regard high-pitched male voices as "unattractive", preferring deeper male voices "especially during the most fertile phases of their menstrual cycles".
The report concluded: "This study provides evidence that both sexes tended to lower the pitch of their voices when communicating with more attractive targets.
"A low-pitch voice for male speakers has been shown to relate to masculinity, higher reproductive fitness and increased ratings of men's social and physical dominance. Therefore, it may be an advantageous manipulation on the part of males to lower their voices in order to obtain females with greater mate value." - Mail on Sunday