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Gender Behaviours Inherited from Social Environment

The different ways men and women behave can be inherited from our social environment – not just from genes. In a report in Trends in Cognitive Sciences, Prof Cordelia Fine of The University of Melbourne and colleagues showed how interactions between the genetic and hormonal components of sex create variability between individuals while environmental factors supply the stable conditions needed for the reproduction of the trait in each generation.

“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,” explained coauthor Prof John Dupré of The University of Exeter. “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.”

Co-author Prof Daphna Joel of Tel-Aviv University found that human brains are composed of unique mosaics of features, some more common in one sex and some more common in the other. Joel said: “Masculine and feminine behaviours cannot be explained by the existence of male and female brains... Our research suggests that intergenerational inheritance of gender-specific traits may better be explained by highly stable features of the social environment.”

The report says 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. Fine said: “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.”