Sex determination and differentiation (human)

Hey kiddo, do you remember when we talked about how a baby is made? Well, sometimes a baby can grow up to be a boy or a girl or somewhere in between, right? That's what we call sex determination.

Now, before a baby is born, their body needs to decide whether it will be a boy or a girl. This happens because of something called chromosomes, which are like little instructions in our cells. Girls have chromosomes called XX and boys have chromosomes called XY.

When a baby is conceived, it gets one chromosome from its mom and one from its dad. If the baby gets two X chromosomes, it will develop into a girl. If the baby gets one X and one Y chromosome, it will develop into a boy.

Now, once the baby’s determined its sex, its body will develop in a certain way to look like a boy or a girl. This is called sex differentiation. The hormones in the baby’s body play a big part in it. Hormones are like little messengers that tell our body what to do.

For example, girls have ovaries which produce hormones called estrogen that help their bodies develop breasts and a more rounded figure, while boys have testes which produce hormones called testosterone that help their bodies develop muscles and facial hair.

All of these changes happen over time as the baby grows into a child and then an adult. And that's how sex determination and differentiation work in human beings!