Evidence is not fact, it is still someone's opinion. You have a stronger opinion because its a topic that's personal to you. That still does not make it true.
The exact cause of gender dysphoria is still unclear.
It was traditionally thought to be a psychiatric condition, with its causes believed to originate in the mind.
However, more recent research suggests the condition may actually be the result of the abnormal development of a baby while it is in the womb, possibly as a result of genetic or hormonal factors, which causes the brain to develop a gender identity that is different to the baby's sexual organs.
Which is what I posted a few pages back...