[Gender in the brain. A critical scrutiny of the biological gender differences].

Down through history, biological arguments have often been used to legitimize a social gender order characterized by male supremacy. In the 1990's, a lively debate on the biological grounds of gender differences once again emerged in various fields. In the present article, the biological models used for explaining cognitive and behavioral gender differences are scrutinized, and recent research is discussed in light of history. These biological models emanate from theories about sex hormones, genetics and brain anatomy. Regarding the cognitive effects of sex hormones, no consensus has been reached, indicating a need for further research. Studies of relationships between genetics on the one hand and sexual orientation and behavior on the other are theoretically obscure and have thus far failed to prove a trustworthy connection. While there is indeed a difference in total brain size--men's brains are heavier than women's--it is not known whether this difference has any import beyond the fact that men have larger bodies. The existence of differences in brain lateralization and the size of the corpus callosum have been powerfully dismissed in several recent reviews. The design and interpretation of medical research in this field are still colored by gender-stereotyped preconceptions and expectations, which obstructs efforts to gain a solid understanding of the biological differences/similarities between men and women. The media's interest in publicizing research results on gender differences, irrespective of magnitude or practical significance, further alerts us to the importance of scientific reason. There exists a very real risk today that medical gender research may be reduced to research about differences. If this problem is not addressed, it might lead to the reinforcement of the gendered structures of society.