German Boy began sex change treatment at 12

Spiegel Online 26 Jan 07
A German adolescent is believed to have become the world’s youngest sex change patient at the age of 12, after convincing doctors that he wanted to live the rest of his life as a female. In a story headed “Mistakes in God’s Factory,” the German magazine Der Spiegel tells how 14-year-old Kim P was Tim until two years ago. But from the age of two Tim had tried on his older sister’s clothes, played with Barbies and said, “I’m a girl.”
From the age of four his parents went along with his girl behaviour and he became “Kim”.

http://www.spiegel.de/international/spiegel/0,1518,462516,00.html