Have you been checking up on your man more often these days? You know -- going through his phone, reading his Facebook messages, asking him why that new receptionist at his job looked at you sideways? One last question: are you on the pill? A new research study found that taking the pill can heighten a woman's feelings of jealousy and possessiveness, Lemondrop.com reported. Women in the study were given hormonal birth control pills with different doses and asked a number of questions about their relationships, like, "how they feel when their other half flirts with another woman" and "whether they were worried that he would leave them for another woman." Researchers found strong connection between synthetic estrogen and a woman's desire to check any ladies trying to push up on her man. The next time you think about following your man to work, press pause and check the estrogen level on your pill box. And the next time your man calls you crazy, blame it on the pill.