Baku, February 22 (AZERTAC). WOMEN, the next time the man in your life complains you talk too much, silence him with science.

Tell him - at length, of course - it is all because of the Foxp2 protein.

It has been claimed previously that women speak about 20,000 words a day - some 13,000 more than the average man.

But now scientists at the University of Maryland in Baltimore, US, have found the key to explaining why women are the more talkative sex.

A study published in the Journal of Neuroscience suggests that higher levels of the protein are found in the female brain.

US researchers found that those with more Foxp2, known as the "language protein", in their brains were the chattier. Among humans that was women, but in rats it was the males.

The researchers set out to determine what might make male rats more vocal than their female cage mates. They separated four-day-old pups from their mothers and counted the number of times they cried out.

Both male and female pups emitted hundreds of cries, but the males called out twice as often. As a result, when the pups were put back in the same cage as their mother, she fussed over her sons first.

Tests on the parts of the brain known to be involved in vocal calls showed the male pups to have up to twice as much Foxp2 protein as the females.

The researchers then ramped up its production in the brains of female pups and reduced it in males. This led to the female rats crying out more often and their mothers showing more interest to them.

The males in contrast, became less "talkative". Next, the researchers tested samples from ten boys and girls aged between three and five.

This showed the girls to have 30 per cent more of the Foxp2 protein than the boys, in a brain area key to language in humans.

Researcher Margaret McCarthy said: "Based on our observations, we postulate higher levels of Foxp2 in girls and higher levels of Foxp2 in male rats is an indication that Foxp2 protein levels are associated with the more communicative sex."

Studies have shown that the female love of chit-chat begins at a young age. Girls learn to speak earlier and more quickly than boys. They produce their first words and sentences earlier, have larger vocabularies and use a greater variety of sentence types than boys of the same age.

However, Simon Fisher, one of the Oxford team who first pinpointed the protein, cautioned against drawing big conclusions from a study of such a small number of children.