The next time you see your woman acting overly jealous or possessive, you might want to take a peek into her medicine cabinet, for it might be the Pill to blame.
A study by Stirling University's Dr Craig Roberts claims sex hormones in the contraceptive Pill bring out the green-eyed monster, making a woman more possessive and more likely to fret about her husband or boyfriend's fidelity.
The drug is also credited with making women broody, changing their taste in men and even boosting intelligence.
Progesterone, however, was not implicated in jealousy, suggesting that progesterone-only versions of the Pill play less havoc with women's emotions.
"It seems that women, and perhaps pharmaceutical providers, are not fully aware of the range of potential psychological side-effects associated with pill use and more specifically brand choice," The Daily Mail quoted Roberts as saying.
Other studies have suggested that the Pill makes certain areas of women's brains bigger, makes women broody and may also alter a sense of smell.
The study is published in the journal Personality and Individual Differences.