When the Harvard sociologist Hilary Levey Friedman was expecting her first child, one thing worried her: her due date, January 3rd. It was uncomfortably close to January 1st, an often-used age cutoff for enrollment in academics and sports. “I was determined to keep him in until after January 1st,” she said. And if the baby came early? “I actively thought about redshirting,” she said. Given the choice, she wanted him to be the oldest kid in his class, not the youngest.