The physical, emotional, and social milestones of every girl's life: what we've lost and gained in the 21st century. The physical, emotional, and social milestones of every girl's life: what we've lost and gained in the 21st century. Caitlin Flanagan's essays about marriage, sex, and families have sparked national debates. Now she turns her attention to girls: the biological and cultural milestones for girls today, and how they shape a girl's sense...