Gene Discovery May Aid Transgender And Intersex Therapies

Scientists have discovered a genetic "on-off" switch that tells the body what gender it is.

An international team found that the action of a single gene is all that stops females from developing male physical traits, including testes and facial hair. When this gene was artificially “switched off” in adult female mice their ovaries began to turn into testes and they started to produce a level of testosterone found in healthy male mice. The discovery could eventually revolutionise gender reassignment therapy and improve treatments for babies who are born with a mixed gender. The research, published today in the journal Cell, challenges a common perception that gender is determined purely by the X-chromosomes and Y-chromosomes. The gene that was switched off, known as FOXL2, lies on a non-sex chromosome that is shared by males and females.

Researchers had merely expected the female mice to stop producing eggs. Other than the change in gender characteristics, the test animals appeared to experience no other physical changes and lived a normal lifespan.