Seventeen-year-old Josh Alcorn from Ohio jumped in front of a lorry after leaving a one thousand word suicide note on social media website Tumblr.
In the letter he spoke about how he had struggled with his sexuality for a long time and felt like he was a girl trapped in a boy's body from the age of 4.
He said only in his teenage years did he realise there were others like him: "After 10 years of confusion I finally understood who I was.
"I immediately told my mom, and she reacted extremely negatively, telling me that it was a phase, that I would never truly be a girl, that God doesn't make mistakes, that I am wrong.
He said the way his parents handled the situation caused huge damage to him.
"My mom started taking me to a therapist, but would only take me to Christian therapists, (who were all very biased) so I never actually got the therapy I needed to cure me of my depression," he said.
"I only got more Christians telling me that I was selfish and wrong and that I should look to God for help."
His parents have rejected the idea that they were unsupportive. His mother, Carla told CNN: "We told him that we loved him unconditionally.
"We loved him no matter what. I loved my son. People need to know that I loved him. He was a good kid, a good boy."
Police in Ohio say they're investigating the death as a suicide.