Hi there! Degeneration theory is a complicated idea, but I'll explain it in a way that you can understand.
You know how sometimes things break down and don't work as well as they used to? Maybe your toy car stops rolling or your crayon keeps breaking when you try to color. Well, scientists used to think that people could "break down" too. They believed that certain groups of people were more likely to become "degenerated" than others.
This idea was called degeneration theory. Basically, it said that if you were born into a poor family or a family with certain characteristics (like being from a particular race or having a mental or physical disability), you were more likely to become a degenerate. That meant you wouldn't be able to think clearly, control your emotions, or behave properly.
But degeneration theory was really wrong! Scientists eventually learned that people's behaviors and abilities aren't determined by their race, class, or family background. Instead, everyone has the potential to learn and grow, and it's important to treat people with kindness and respect no matter where they come from.