The moment that started martha mcclintock’s scientific career was a whim of youth. Even, she recalls, a ridiculous moment. It is summer, 1968, and she is a Wellesley College student attending a workshop at the Jackson Laboratory in Maine. A lunch-table gathering of established researchers is talking about how mice appear to synchronize their ovary cycles. And 20-year-old McClintock, sitting nearby, pipes up with something like, “Well, don’t you know? Women do that, too.”