This was one of my first freelance pieces after leaving my staff media job at PNAS. I will always be thankful to Emily Willingham at DoubleXScience for taking me on and commissioning this story. It was also picked up by Popular Science, which was thrilling for me as a noob. Four years later, I still get a few emails a year about this piece, usually from women who have experienced arousal during rape, or concerned family members. My research took me down a dark hole of human c