Is there a way to limit a parent object's child count to only 1 without individually doing it with each transform?

I have a pool of children that randomly activates under a list of parents, problem is I only want the parents to have one child each but since its randomized, sometimes a parent hosts more than one child. It's not pleasant to have to individually detail the transform for each of the 20 children, which may grow in the future.

thisVar = obj1[Random.Range(0,obj1.Length)]; // Attatch it to the tiles randomly children.transform.parent = thisVar.transform;