Human sexual identity is studied

ATLANTA, Oct 10, 2005 (UPI via COMTEX) -- Research in Atlanta may explain the interaction among the brain, physiology, and behavior that forms the biological basis of human sexual identity.

While changing sex from female to male, the highly social bluebanded goby becomes more aggressive and, at the same time, the conversion of testosterone to estrogen slows in the brain, but is unaffected in the changing gonads, according to a Center for Behavioral Neuroscience study.

The finding, which suggests the initial stages of sex change in fish are regulated in the brain, might help explain the biological basis of human sexual identity.

As do many fish species, the bluebanded goby switches sex in response to changes in its social environment.

In the study, CBN researcher and Georgia State University biology professor Matthew Grober and colleagues attempted to determine the correlation between behavior and sex hormone conversion. The researchers found dominant, sex-changing females and recently sex-changed males had lower brain aromatase levels than control females. Control males had the lowest brain aromatase levels and lower gonadal aromatase levels than all groups, except the sex-changing females.

The study is detailed in the on-line edition of Proceedings of the Royal Society B.

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