Shrill voices reveal it's nearly time for pillow talk

Women's voices rise and fall in tune with their fertility, according to research by psychologists. Recordings taken at different times in the monthly cycle show that the female voice rises a day or two before ovulation, when women are most likely to become pregnant.

The findings are the first to point to a link between voice and fertility, and build on recent studies which support the idea that humans may be similar to other animals in displaying outward signs of fertility. Greg Bryant, a psychologist at the University of California, Los Angeles, who led the study, says that by raising the pitch of their voices, women might be perceived as more feminine at the most fertile time in their cycle.

"We found that women raised their pitch the closer they were to ovulation, but it's not like a baboon's butt going red, which is a definite signal of high fertility. This is something more subtle. A man wouldn't notice the pitch being higher if they'd never heard the woman talk before. What we're saying is by raising their pitch, women enhance their femininity. They're turning up everything that makes them more attractive," says Bryant.