The "don't ask, don't tell" policy - which stops people revealed to be gay serving in the US military - is currently the subject of legal action. A law ending the policy and allowing gay people in the military to be open about their sexuality has been signed by President Barack Obama, but could take months to be put into effect.
Here two men forced out of the US military under the policy give their side of the story.
The F-15E Strike Eagle veteran
Lt Col Victor Fehrenbach has served in the US Air Force for nearly two decades, flying in F15-E Strike Eagles in the former Yugoslavia, Afghanistan and Iraq. Having flown 88 combat missions, he has been honoured for heroism for an attack on an enemy ambush site under heavy fire.
He has been taking legal action to fight dismissal after being outed two years ago, while defending himself against allegations of sexual assault. If he is fired before his 20-year mark he will lose his pension.
"My parents were both air force. I grew up on an air force base.
"My case first came up in May 2008. I was basically outed by a third party. This person accused me of a crime, made up a false allegation.
"In the process of telling the truth and proving my innocence, I revealed my sexual orientations and that triggered things. Four months later I was served with the papers. In April 2009 I went before the administrative board.
"For almost another year it's gone through the administrative process.
"I've always thought 'don't ask, don't tell' was wrong and unconstitutional. But I just thought I would keep my private life private and do my military job. I never intended to out myself.
"A lot of people don't realise you can't tell your friends, you can't tell your mother. They might inadvertently say something. Somebody could overhear a conversation.
"Every day you are looking over your shoulder, wondering if you have said something wrong, if you are in a relationship you are constantly thinking of stories to explain if someone spots you together. You feel any day it could happen.
"I flew fighter jets. It required 100% concentration. Somebody else could talk to a buddy about personal problems. We just can't do that.
"I've got a lot of messages from people I've been in combat with. They don't care. They would go to war with me tomorrow.
"We are in the middle of two wars - we need every single bright capable talented person we keep throwing out.
"If I was fired tomorrow, I'd have served 95% of my commitment, but you've got to do the full 20 to get a pension. I would get nothing for my 19 years."
The aspiring pilot
Former US Air Force staff sergeant David Hall was dismissed for being gay eight years ago.
Since then he has worked with the Servicemembers Legal Defense Network to overturn the "don't ask, don't tell" policy.
"I served in the air force for five years, loading bombs and missiles on F-15 aircraft.
"They let me out so I could go into air force reserve officer training corps and come in as an officer.
"It was a two-year programme. After one year a female cadet went to my commander and told him I was gay.
"My boyfriend was also a cadet. He was friends with her. That's how she knew.
"She was a bad cadet. It was a way to get them to leave her alone and get them to focus on somebody else. When they say don't ask, don't tell, they mean don't tell anybody, ever.
"It is basically saying you are not supposed to have any friends, you are not even supposed to tell your family. It is ridiculous. They are basically telling you to lie about who you are.
"I was ranked number one in my class. I had a pilot's slot - I would have had the opportunity to fly.
"I was doing everything the air force asked. I was in Saudi Arabia, Kuwait and south Korea. In return I got fired.
"My dad and my stepdad both served 20 years in the air force. Growing up around the air force I knew it was a good thing to do. I decided to follow in their footsteps.
"I would much rather be doing that still.
"The whole notion about unit morale cohesion being harmed is wrong. What really hurts unit cohesion and morale is to take somebody who is really good at their job and fire them."