"In every final scan we could see a big, full bladder, even though most of the women went to the toilet before they went inside the MRI,” explains Pek with comical astonishment. “We think it might be evolution’s way to force women to urinate after sex. Perhaps our ancestors developed this function to avoid urinary tract infections, but that’s only a hypothesis."

https://www.vice.com/en/article/qvgkzw/the-story-of-the-dutc...