Gender role, which refers to the cultural expectations as understood by gender classification, is not the same thing as gender identity, which refers to the internal sense of one's own gender, whether or not it aligns with
Definition of butterfly effect : a property of chaotic systems (such as the atmosphere) by which small changes in initial conditions can lead to large-scale and unpredictable variation in the future state of the system
So a principal lesson of the butterfly effect is the opposite of Redford's line: It is extremely hard to calculate such things with certainty. There are many butterflies out there. A tornado in Texas could be caused by a butterfly in Brazil, Bali, or Budapest. Realistically, we can't know.