Temperature-dependent sex determination

Okay kiddo, so you know how there are different types of animals like cats, dogs, and fish? Well, some of these animals have a special way of deciding if they will be a boy or a girl. This is called sex determination.

In some animals, like humans and dogs, sex determination happens before they are born and is based on the chromosomes they get from their parents. But in some other animals, like turtles and crocodiles, the temperature of the place they grow in can decide if they will be a boy or a girl. This is called temperature-dependent sex determination or TSD for short.

Let's say we have turtle eggs. If the eggs are kept at a really cool temperature, only boys will be hatched. If the temperature is a little bit warmer, both boys and girls will be hatched. And if the temperature is really warm, only girls will hatch!

This happens because the temperature can affect how the baby turtles' genes work. Genes are like little instructions that tell the animal's body what to do. In TSD animals, some genes work differently in males than they do in females. So if the temperature is just right, those genes will work together to make the animal either a boy or a girl.

Isn't that cool? So some animals don't need chromosomes to decide if they will be a boy or a girl, they just need the right temperature!