So it's all down to one gene - gender that is!

[martin48]

www.independent.co.uk/news/science/from-minnie-to-mickey-and-all-they-did-was-turn-off-a-gene-1838170.html

[SarahG]

www.independent.co.uk/news/science/from-minnie-to-mickey-and-all-they-did-was-turn-off-a-gene-1838170.html

Not really one gene, it's more like a bunch of switches in series where each has to be in the "male" position for the fetus to develop into a guy. If any one of the switches is in the wrong position, it won't work.

So you could, in theory, take any GB, genetically modify them so that just any one of the switches is "wrong," and they'll develop into a girl instead of a guy. BUT, they'd be sterile as girls which means they wouldn't quite be the same as GG's biologically speaking. In every way outside of reproduction, yes.

Most GG's have the X-chromosome gene, but since they don't have the ones on the Y chromosome (because they don't have one), they don't develop into guys.

Related to this what's known as "Y decay (http://www.google.com/#hl=en&safe=off&q=y+chromosome+decay&aq=f&aqi=&oq=&fp=b36c7832dbb01be6)." The theory is that as time has gone on, the Y chromosome has entered into a state of decay, slowly loosing genetic data. What that means in the long run is anyone's guess.

[rockabilly]

It means the chromosone divided by zero.