As far as a military recruiter was concerned there wouldn't be any difference, would there? - you're out regardless of what might be going on in your head.

Meanwhile, a bizarre spin on the story from the BBC (the US military spends 10 times as much on Viagra as on transgender-specific medical care):

Why does the US military buy so much Viagra?

Soldier, soldier won't you marry me,
with your little blue subsidized pill?
How could I marry such a pretty girl as you,
without my sildenafil?...