Originally Posted by KarenNC:
I believe this may be what the poster is referencing:
Mammalian embryos begin with the potential to develop both the male and female reproductive organs–the Wolffian and Mullerian systems (though they from conception have either a male or female chromosonal pattern based on X and Y chromosones). The development of these reproductive organs is dependent upon a complex interaction of the chromosones, hormones, etc. the Wolfian system develops into the male reproductive organs and the Mullerian into the female.
The Mullerian is the default. In the absence of the Y chromosone (or if it does not function properly for some reason), the Mullerian system will develop. If the person is chromosonally XY but the Y does not function properly, that person will be visually female (though there may be other issues related to it in terms of physical development and functionality) and may never know otherwise unless a chromosone test is done.
The remaining questions I have:
Can a person who at conception has X chromosome(s) but no Y chromosome(s) take on Y chromosome(s) later in life? Conversely, can a pesron with a combination of X chromosome(s) and Y chromosome(s) lose one’s Y chromosome(s)? If you know of such cases, I’d like to hear them, because I haven’t seen any evidence to suggest this is possible.
I understand male to be a person who has at least one X chromosome and one Y chromosome. A female has X but not Y chromosome(s). At conception one either has X without Y or X and Y. There is no YY syndrome.
Just because a person has certain characteristics of another sex does not mean the person is that sex.
For example, just because a person goes through life thinking one’s parents are one’s biological parents, based on what one is told and based on all good appearances, does not disclude the possibility of the fact that the person’s parents are not the true biological parents, but only perhaps the foster parents of a bastard son in the blood family. Only a genetic test can tell the person whose one’s real parents are. Likewise, although a person appear to be female in many ways, including one’s physical characteristics, and is viewed as female by others, does not mean the person is female in fact. Only a test can tell.