I'm sure you could.
As far as don't ask don't tell, that worked just fine for me. I didn't want to know. Just do your job.
Security clearances are an entirely different matter. Because if you are outed in the Military you can lose your job homosexuality can become leverage to be used by the bad guys. Even worse the married homosexual can stand to lose everything. His job, his family.
In a small unit their can be no secrets however. They just spend too much time together.