Okay kiddo, so let's say you have two choices for dinner tonight: pizza or spaghetti. You can't decide which one to pick because you like them both the same amount. You're in a state of "equipoise," which means there's balance between the two options and you feel unsure about which one to choose.
Now, let's apply this to something called "clinical equipoise." When scientists are testing a new medicine or treatment, they need to make sure it's safe and effective. They do this by comparing it to something else already in use, called a "control treatment."
However, they need to make sure that the two treatments are balanced, just like how you couldn't decide between pizza and spaghetti. This is where clinical equipoise comes in - it means the scientists believe the new treatment could be just as good as the control treatment, and they don't have a preference for one or the other.
In order to do a fair experiment, the scientists need to keep this balance throughout the study. They can't give one group better treatment than the other, or else the results won't be accurate. By keeping clinical equipoise in mind, they can make sure the study is done in a way that's fair to everyone involved.
So basically, clinical equipoise means that scientists are trying to be fair to everyone involved in a study by not preferring one treatment over the other, just like how you might be fair to pizza and spaghetti.