Ever wonder why so many women in their tween and young teen years and older women in their 50s and beyond go ga-ga for the likes of Justin Bieber and other male singers with soft, feminine-looking faces? A 2010 study in the journal Psychoneuroendocrinology sheds some light on the issue: Turns out, our preferences for facial features changes over the course of our lifetime. Tweens, young teens and menopausal women tend to prefer a feminine appearance while women in their older teen years to late 40s prefer a more rugged, masculine look. As the researchers explain, our preferences go hand-in-hand with our fertility. The more likely we are to be able to conceive, the more attracted we are to potential partners with a robust, virile image since our brains are wired to believe it indicates good health and an ability to protect us from harm!