Evidence
I have cited my sources and am always happy to do so for the instruction of people who genuinely care for the truth, but when people on an opinion forum DEMAND proof for an opinion, they are obviously not interested in the truth at all and only want to silence freedom of expression if they do not like the opinion.
However for what it is worth I will cite a couple of useful BOOKS, "Sex and The Brain" and "Brain Sex". They are reliable and written in a popular style so you do not have to spend your life in Medical Science to be able to understand them as I have, for what it is worth.
I am sure I would be very popular if I were to cite hundreds of pages of books and journals would I ? But that is what determined anti truth people demand. If I did that I would be rightly condemned. But this is an Opinion Forum, not an encyclopedia. All anyone reasonably person has a right to expect from anyone else is what their honest opinion is - not that they be subject to vicous harrasement and slander!