LOS ANGELES, Oct. 20 (UPI) -- A new University of California-Los Angeles study indicates genes drive the brains of male and female embryos apart as early as midway through gestation.
Such gender differences had been assumed to arise around birth due to hormones pumped out by males' budding testes. But Nature.com reported the study found that halfway into a mouse pregnancy, before the testes even formed, the activity of 51 genes was different in males and females.
The study, involving 12,000 brain genes, hints that unknown genes hardwire our gender and, perhaps, influcence the way in which men and women think, tackle problems or perceive themselves.
The study is the first to measure how many genetic differences there are, and to reveal that they occur in such young embryos. The team has not yet determined what the 51 genes do.
Researchers speculate the brains of males who feel that they are female, or vice versa, may have a pattern of gene activity that resembles that of the opposite sex.
