XY sex-determination system
Okay kiddo, so you know how we have boys and girls, right? Well, sometimes in animals and people, whether they end up being a boy or a girl is determined by something called the xy sex-determination system.
Let's start with the xy part. Everyone has chromosomes in their cells, and these chromosomes carry all sorts of important information about how our bodies work. One of those pieces of information is whether we're a boy or a girl. In the xy sex-determination system, there are two types of chromosomes: X chromosomes and Y chromosomes. Girls have two X chromosomes, and boys have one X and one Y chromosome.
Now, it might seem like a 50-50 chance of being a boy or a girl, right? But actually, the sex of a baby is determined by the father's sperm. If the sperm has a Y chromosome, it will fertilize the mom's egg and the baby will be a boy. If the sperm has an X chromosome, the baby will be a girl.
So, to sum up: the xy sex-determination system is how some animals and people determine whether they'll be a boy or a girl. It's determined by the father's sperm carrying either an X or a Y chromosome, and it's all part of the information that's carried in our cells on our chromosomes.
Let's start with the xy part. Everyone has chromosomes in their cells, and these chromosomes carry all sorts of important information about how our bodies work. One of those pieces of information is whether we're a boy or a girl. In the xy sex-determination system, there are two types of chromosomes: X chromosomes and Y chromosomes. Girls have two X chromosomes, and boys have one X and one Y chromosome.
Now, it might seem like a 50-50 chance of being a boy or a girl, right? But actually, the sex of a baby is determined by the father's sperm. If the sperm has a Y chromosome, it will fertilize the mom's egg and the baby will be a boy. If the sperm has an X chromosome, the baby will be a girl.
So, to sum up: the xy sex-determination system is how some animals and people determine whether they'll be a boy or a girl. It's determined by the father's sperm carrying either an X or a Y chromosome, and it's all part of the information that's carried in our cells on our chromosomes.