Yes, they do have something in common. Squalene, a compound found in the vagina, is a natural lubricant. When a woman is aroused, squalene is secreted allowing the clitoris and labia to swell up and prepare the body for sex. In sharks, however, squalene is far less sexy. The compound is found in the livers of sharks and is believed by some cultures to have miraculous effects. The local people on the Japanese peninsula of Izu, for example, refer to the substance as “Samedawa” or a cure-all, believing it can heal a variety of diseases, ranging from constipation to cancer.