The number of children born "intersexual" and the subsequent decision of a doctor to perform surgery (for aesthetic or social purposes) to "assign" a gender is much higher than many would ever know. This can lead to gender confusion, as you can guess; some kids notice it earlier especially in these days of much more openness about gender issues.
I don't find the article or issue all that surprising.
http://en.wikipedia.org/wiki/Intersex
http://www.bbc.co.uk/dna/collective/A843176