It is odd to constantly hear Christians fall back on the scientifically proven facts about chromosomes and their role in human development and then to completely ignore the actual, scientific fact that it’s not as simple as XX and XY.
On contrary, it IS as simple as X and Y. The chromosomal abnormalities that you refer to in your post are the result of non-disjunction during one of the two divisions of meiosis which is the process by which gametes (eggs and sperm) are formed. Depending on when it occurs, some of the cells end up with no X or Y and some end up with two. If they are fertilized by a normal gamete that has only one sex chromosome, you can end up with XO, XXX, XYY, etc. Since there are very few genes on the Y, a zygote without at least one X is not viable.
My caution to these trans-gender advocates is that, no matter what you do to change the outside or inside of your body with hormones or surgical procedures, there is NO WAY to change what is inside the nucleus of all of the somatic (non-sex) cells of your body. Except for the chromosomal abnormalities mentioned above, your cells will have two X chromosomes (biologically female) or one X and one Y (biologically male).
By the way, I am both a Christian and a biologist and scientist. I have a MA degree in Biology and a degree in Medical Technology. I have been teaching both subjects at my local community college for over 36 years.