Staff sergeant and squad leader Patricia King. Patricia King For 16 years, Patricia King was indistinguishable from the platoon of male soldiers around her.

She served three tours as an infantryman for the US army in Afghanistan in 2001 - 2002, 2003, and most recently in 2013 - 2014, rising to become staff sergeant and squad leader.

King has worked across Afghanistan's mountainous regions, as well as in the busy streets of Kabul: her roles ranged from processing detainees destined for the hell of Guantanamo Bay, to providing security for generals travelling across the war zone.

Back home in Colorado, King had a wife and sons. King was born with the biological characteristics of a man, but a sense of body dysmorphia had tormented her since she was eight. Nevertheless, she appeared to flourish in what she calls the "hyper-masculine" environment of the US army.

Things suddenly changed last June, when staff sergeant Patricia King became the first infantryman in the US army to come out as transgender.

To understand how courageous this decision was, it is important to be aware of the fact that her employer — the US army — maintains that it is a "dischargable offence" to be openly transgender.

However, in July 2015, in an unprecedented move for the US army, Defense Secretary Ash Carter announced a rethink of the policy in a statement to the press:

"At a time when our troops have learned from experience that the most important qualification for service members should be whether they're able and willing to do their job, our officers and enlisted personnel are faced with certain rules that tell them the opposite. Moreover, we have transgender soldiers, sailors, airmen, and Marines - real, patriotic Americans - who I know are being hurt by an outdated, confusing, inconsistent approach that's contrary to our value of service and individual merit."

Nearly one year on, a formal change of rules has yet to be announced. According to the rules, King could still be fired from her job for living true to her identity — though in practice this is unlikely.

Business Insider caught up with King to find out more about life as a transgender soldier in the US army, and her expectations for the future.