NEWS.COM.AU - Dec 19 - Scientists have discovered that the major sign of sexual chemistry when people meet for the first time is to do with the voice. Anthropologists from the UK's University of Sussex trawled speed dating events and recorded potential matches chatting to see if there were patterns they could identify. Lead author Dr Katarzyna Pisanski said men were found to lower the pitch of their voice when they found someone they wanted to see again in the future - and the tone deepened even further if the lady was particularly desirable. Women spoke in a higher-pitched and less monotone voice on speed dates with men they chose as potential mates. However, if they sensed that a man was in strong demand, the higher-pitched vocals switched to significantly deeper pitches.