I used the phrase "most likely caused" because it is the most viable theory at this point. And, frankly, it makes perfect sense looking at the function and effects of hormones. From the little I have read they have ruled out basic genetics and childhood events. It is just not something that scientist study much, it is a very recent subject and not focused on.
And, you should look up what an Argument from Ignorance Fallacy is, I'm not even close.
"In the beginning of a change the patriot is a scarce man, and brave, and hated and scorned. When his cause succeeds, the timid join him, for then it costs nothing to be a patriot."--Mark Twain