how do I scale my Instanciated GameObject to a parent gameObject that varies in scale?

I have a Mother game object, which has a group of Child game objects.Each Child game object spawns a ball through Instanciation.

In my game, the player is able to scale Mother (which in turn, scales all the Child objects).

However, whenever the Child spawns the ball, the ball's scale isn't to the child. It either ends up being too small when Mother is scaled up, or too big when Mother is scaled down.

The ball itself is a prefab. How can i make it scale so that it'll be the same size as the child?

to have an idea, because child's parent is Mother and when the player scales the Mother, only the Mother's scale changes (the child's scale is still 1)