I always wondewred if was a female plot, know we now it is genetic!
In a study to be published in the journal Biology of Reproduction, researchers collected samples from the underarms of men who refrained from using deodorant for four weeks. The extracts were then blended and applied to the upper lips of 18 women, aged 25 to 45.
The women rated their moods on a fixed scale for a period of six hours. The findings suggested something in the perspiration brightened their moods and helped them feel less tense. Blood analyses also showed a rise in levels of the reproductive luteinizing hormone that typically surge before ovulation.
http://www.cnn.com/2003/HEALTH/03/15...eut/index.html