Why is turning 30 a cultural phenomenon—and, usually, not in a happy way? Evolution tells us women are physiologically prime to be at our peak during our early to mid-thirties. As such, there are often expectations of social milestones such as marriage and raising a family. For some women, turning 30 signifies "the end of youth." Dr. Kirtly Jones discusses the biological and social significance of turning 30 for women, and how the milestone age impacts the seven domains of our lives.