Social environment can shape male, female behaviours

Besides genes, human environment and culture can also influence gender-specific behavioural traits, claims a research. For some masculine and feminine behaviour-related traits, the interactions between the genetic and hormonal components of sex with other factors create variability between individuals.

On the other hand, environmental factors supply the stable conditions needed for reproduction of the trait in each generation, the researchers said.
"Even in non-human mammals, adaptive traits that have reliably developed in offspring for thousands of years can disappear within a few generations if the relevant environmental conditions change," said John Dupre from University of Exeter in the UK.

"Genetic inheritance continues to be critical for the capacity to quickly learn an adaptive behaviour, but environmental factors that are stable over generations remove any selective pressure for the development of parallel genetic mechanisms," Dupre added. For the study, published in the journal Trends in Cognitive Sciences, the team reviewed studies on evolution and relationship between sex and brain.

As part of another study, Daphna Joel, Professor at Tel-Aviv University in Israel, found that human brains are composed of unique mosaics of features, which are more common in one sex. "Our research suggests that intergenerational inheritance of gender-specific traits may better be explained by highly stable features of the social environment," Joel noted.

According to the research, non-genetic mechanisms may be particularly important in humans because our culture strongly encourages us to have male or female roles. The enormous human capacity to learn also allows for information to be passed from generation to generation.

"The conclusion is the need to question the pervasive assumption that it is always biological sex, via its direct action on the brain, that does the 'heavy lifting' when it comes to the gender traits we inherit and display," said Cordelia Fine from the University of Melbourne.