The man's nose knows when a woman is fertile, scientists say

Jan 30, 2006, 5:32 GMT

Prague - Men who nose around their partners may detect a special odour emanating from under women's arms during the fertile period of their monthly cycle, Czech scientists report.

A woman's 'most attractive' and 'least intense' armpit odour is emitted during fertility, according to a research team led by anthropologist Jan Havlicek of Prague's Charles University.

The conclusions, based on 'sniff tests' involving 12 women and 42 men, were published recently in the journal Ethology.

Initially the researchers were puzzled by the traditional mysteries surrounding human fertility.

'Females of a number of primate species display their fertile period by behavioural and-or morphological changes,' they wrote. 'Traditionally, the fertile period in human females has been considered to be concealed.'

Their search for a simple way to detect human fertility led to the armpits.

Sample smells from 12 women, ages 19 to 27, were collected from cotton pads in their armpits held for three, 24-hour periods during the course of their monthly cycles.

Then 42 men, ages 19 to 34, were asked to rate the odours according to 'intensity, pleasantness and attractiveness.'

The odour from women in the fertile phase 'was rated as the least intense and the most attractive,' the researchers said.

'Our results suggest that men can potentially use smell as a mechanism for monitoring menstrual cycle phase in current or prospective sexual partners,' they said.