Leopard geckos

The sex of their offspring is determined by the temperature within the first two weeks after an egg is laid.

An excerpt from the article 20 facts about Leopard geckos
In cooler temperatures like 26 °C - 29 °C (78,8 °F - 84,2 °F) more females will be produced, and more males in warmer temperatures like 34 °C - 35 °C (93,2°F - 95 °F).