Original: In some turtles, for example, males are produced at lower incubation temperatures than females; this difference in critical temperatures can be as little as 1-2°C. Many fish change sex over the course of their lifespan, a phenomenon called sequential hermaphroditism.
Simplified: In some turtles, for example, males are produced at lower incubation temperatures than females; this difference in critical temperatures can be as little as 1-2°C. Many fish change sex over the course of their life.