"I will continue to fight until the day I can remain to serve in the army. I'll challenge the decision until the end, to the Supreme Court," she said.
She had not planned on having gender reassignment surgery, she said, but was recommended to do so by doctors at a military hospital where she was sent after suffering mental health problems. They arose from gender dysphoria - defined as distress from the internal conflict between physical gender and gender identity.
"It was an extremely difficult decision to let my base know of my identity, but once I did, I felt much better," she said.
"I thought I would finish serving in the army and then go through the transition surgery and then re-enter the army as a female soldier. But my depression got too severe," she added.
...
But Lim Tae-hoon from the Center for Military Human Rights said Ms Byun's discharge was unusual because it was effective the day after the decision was made. Usually they are effective after a period of up to three months, he said. It suggested that the army did not want Ms Byun to have contact with her unit, Mr Lim said.
An army official who was aware of the case told Reuters news agency there should be no reason for the military to deny Ms Byun if she reapplied to serve in the female corps after legally becoming a woman.