Study links gene that could stop one from becoming a boy

8220;An extra copy of DAX1 in male babies blocks the development of the testicles entirely, and this is responsible for some cases of disorder of sex development DSD,8221; Louisa Ludbrook, who led the study, said.

Using cells in culture, Ludbrook and colleagues at Prince Henry8217;s Institute in Melbourne found that increasing copies of the gene DAX-1 could block the production of a potent male factor, called SOX9. This factor is important in most animals with testicles.

8220;A common requirement for testicle development, conserved between species as diverse as humans and reptiles, is an increase in production of the gene SOX9. When SOX9 production reaches a certain level, testicles, rather than ovaries, will develop.

8220;By knowing exactly the point when development of the testicles is blocked, we can help parents and doctors decide on the best treatment options for these kids, be it hormone therapy or surgery.8221;

8220;And studying these kinds of conditions also helps us understand the broad sweep of human sexual development,8221; said Vincent Harley, Head of Human Molecular Genetics unit, Prince Henry8217;s Institute.