Feeling female can be an early indication that you are a woman.
> I do not deny that gender dysphoria is a clinical diagnosis, but that does not mean we should enable an unhealthy behavior.
On the off chance you actually care about Chelsea Manning's health, please stop referring to her as "he."
This situation is typically referred to as gender dysphoria - the mismatch of sex assigned at birth with gender identity. For some trans people (Manning included) the most effective ways to resolve gender dysphoria may include hormone replacement therapy or surgery. There are lots of good articles on this if you want to read more about it, including a very good piece by a clinical psychiatrist for the NYT. [2]
[1] http://nymag.com/news/features/bradley-manning-2011-7/index4...
[2] https://www.nytimes.com/2015/08/23/opinion/sunday/richard-a-...
The absolute worst disservice we - as random onlookers - can do to people with gender dysphoria is to deny their sense of self.
Please try not to.