Do you know what one of the many things that bites about going to the doctor whilst trans is? Interpreting the results of medical tests.
Medical types divide the world into two arbitrary groups, men and women. They then proceed to treat each as a separate population, and arbitrarily decide which ranges of which measurements constitute healthy, not-quite healthy, and in need of expensive pills.
Thankfully, my doctors and I are typically in agreement that I'm a woman. However, I'm not sure how many women in said population have gone through puberty twice. This might skew the validity of arbitrary conclusions about my health.
I'm sure many folks can think of other analogous situations.