The hatching sex of turtle eggs is really affected by the external temperature, but the temperature changes very little. Eggs buried in the same pit have different depths and different soil temperatures, so there are always males and females in a litter of small turtles. Only when the temperature in the laboratory is completely isothermal can humans find that turtle eggs are sensitive to environmental temperature, while the temperature in the field changes greatly, so there is no need to worry about the gender imbalance of turtles.

Your second question is very interesting, and now the answer is as follows:

Turtles do not passively adapt to the cold climate, they always choose warm places to lay their eggs, so until today, turtles still have to travel thousands of nautical miles to breed in the warm spawning sites chosen by their ancestors.