As I have noted in the past, the XX and XY chromosome patterns are only two of nine patterns found in human beings. There are normal male with the xx pattern and normal females with the xy pattern. Science (maybe you've heard of it) has discovered that the chromosome pattern is not an absolute predictor of gender, in fact they are now using 8 indicators and assinging a probability of gender. Why do you think the Olympics stopped trying to gender type people? There is no absolute way to determine who is male and who is female, there are simply too many overlaps between them.
In the end what we are discovering is that gender is on a continuum from primarily male on one end, through every shade inbetween, to primarily female on the other end. Is there anyone reading this who doesn't know that hermaphrodites (now called "intersexed") people exist? Why would anyone believe that it wasn't possible to have other less obvious gender mixes in humans? Do you even know what the largest sex organ in the human body is? Don't look down, dog, it's not that.