Martha McClintock and Natasha Spencer, psychologists at the University of Chicago, may have found chemical compounds that increase female sexual motivation. Strangely, the potion comes not from hunky men but from breast-feeding women and their infants.
After conducting animal studies hinting that breast-feeding females secrete a substance that increases fertility among other females nearby, McClintock decided to look for the same effect among humans. She asked 26 nursing women to wear absorbent pads under their bras while breast-feeding; she then had other women swipe the pads under their noses several times a day. Each day McClintock administered a standard questionnaire measuring levels of sexual motivation. Women with a regular male partner showed a 24 percent increase while the single women showed a 17 percent rise.
Studying the mechanism behind this effect could yield new treatments for women with low libidos and further establish the reality of human pheromones. The treatments are still a long way off, McClintock warns: “I’d hesitate at this point to even call it a pheromone, because although the substance certainly seems to fulfill those criteria, we have yet to identify the exact component in the pads responsible for the results.” Meanwhile, she is also pondering the evolutionary significance of her discovery. “For most of human history, fertility was limited by the environmental conditions and food available to potential mothers,” McClintock says. “A successful birth nearby would have been the best signal to infertile women that it was a good time to get pregnant.”
