What about C? Well, in C, we describe the situation in male individuals. In males, unlike in females, we only have one X chromosome. And the other sex chromosome is called the Y chromosome. And notice it's much smaller in size and has a slightly different shape than the X chromosome. So, in contrast, male individuals have one X chromosome that contains many different types of genes that code for specific sex link traits and it also contains a small Y chromosome that basically has one or several genes that code for maleness.