I did some reading about this in the internet during my blessed pregnancy time, and I wanted to shout from the bottom of my stomach that it is the men who is responsible for the gender of the baby.
It is yet a big problem,atleast in India - Baby girls.
I personally have come across some families, where the lady of the house is blamed for being incapable to deliver male child. Well, is it a mistake by the way?
Now the matter, the medical stuff that I read is translated in my language.
Women's chromosome is XX, and Men's XY.
Which of these men's X and Y is the dominant at that point of time, and that decides if the baby is going to be XX or XY, I mean a girl or a boy respectively.
XX + Xy is XX -----> Xy by which I mean Dominant X
XX + xY is XY -----> xY by which I mean Dominant Y.
Tail piece: It is the women who is responsible for the number of the babies at one conception, i.e, twins, triplets and more sometime...:-)
I shall try and post the source of this information soon.