J. Michael Bowers, Ph.D., Margaret McCarthy, Ph.D., and colleagues at the University of Maryland School of Medicine examined the sex differences in the expression of the Foxp2 protein and the effect on the developing brain that could underlie communication differences between the sexes.
The researcher found that the Foxp2 protein was substantially higher in newly born male rats. This produced more frequent vocalizations when the male rats were separated from their mother than in female rats. The higher levels of vocalization produced more maternal attention for males.
When the levels of the Foxp2 protein were artificially increased in females and reduced in males the reverse behavior became dominant. Female rats made more noise and male rats were quieter.
A small study of children found that the Foxp2 protein level in girls was higher than in boys of the same age.
This is the first study that defines a specific chemical difference that explains why women talk more than men.
As of yet no correlation of the Foxp2 protein in men who talk more than women has been found but the research leads one to anticipate such a discovery. Dr. McCarthy explains there is no data available but that she would "love to do a study".