Quote Originally Posted by O'Callaghan View Post
I defer to you as the doc, but AFAIK, those women who do have a Y chromosome are not able to pass it on, as they are not fertile. That is a complicated subject in it's own right.
There are women who are genetically XXX, and multiple X, generally. It's quite an abnormal situation but it does occur. You can read about these sorts of sex chromosome abnormalities on the 'web.

However if a person acquires a Y chromosome at all, they will be physiologically "male" if they survive to birth. XXY is rare, but it does occur, the syndrome is called "Klinefelters Syndrome".