Oh Chandni!

"Even so, we find that there are human females with XY chromosomes (very rare) that the male"startup" gene (called the sry gene) apparently did not work. Default is female."
source: here

"Except for the potential contained within the genetic content of its chromosomes and the subsequent formation of primordial tissue, the human embryo is essentially asexual for the first weeks of its life. It has been shown that the undifferentiated gonads are destined to become ovaries unless acted upon by TDF (testis determining factor), which is genetically encoded on the Y chromosome. Therefore the default sex of the human embryo is female. The information for TDF is contained in the SRY (sex determining region of the Y chromosome). It is the translocation of the genes encoding for the TDF to the X chromosome that can result in the abovementioned XX male, who ultimately will be infertile."

hehe, that last bit was funny.

Anyway, Chand and I got into ANOTHER disagreement over the default sex. So we agreed to google it. Muahahaha! See, one of the rare bits of Newsweek articles that I remember. Syok!