Что не так? Может я не правильно понял задание?

public static void main(String[] args) {
        Human grandFather1 = new Human("Heiko",true,83);
        Human grandFather2 = new Human("Hans",true,81);
        ArrayList<Human> grandFathers = new ArrayList<>(); grandFathers.add(grandFather1); grandFathers.add(grandFather2);

        Human kind1 = new Human("Mariya",false,4);
        Human kind2 = new Human("Sem",true,3);
        Human kind3 = new Human("Tomy",true,9);
        ArrayList<Human> childs = new ArrayList<>(); childs.add(kind1); childs.add(kind2);childs.add(kind3);
        childs.add(new Human("krlek",true,34));

        Human grandMather1 = new Human("Gisela",false,78);
        Human grandMather2 = new Human("Ruby",false,76);
        ArrayList<Human> grandMathers = new ArrayList<>(); grandMathers.add(grandMather1); grandMathers.add(grandMather2);

        Human father = new Human("Tomas",true,36,childs);
        Human mather = new Human("Anna",false,35,childs);
        ArrayList<Human> perents = new ArrayList<>(); perents.add(father); perents.add(mather);

        ArrayList<Human> familie = new ArrayList<>();
        familie.addAll(childs);
        familie.addAll(perents);
        familie.addAll(grandMathers);
        familie.addAll(grandFathers);

        for (Human man: familie){
            System.out.println(man.toString());
        }

public static class Human {
        String name;
        boolean sex;
        int age;
        ArrayList<Human> children = new ArrayList<>();

        Human(String name, boolean sex,int age){
            this.name = name;
            this.sex = sex;
            this.age = age;
        }

        Human(String name, boolean sex,int age, ArrayList<Human> children){
            this(name,sex,age);
            this.children = children;

        }

public String toString() {
            String text = "";
            text += "Имя: " + this.name;
            text += ", пол: " + (this.sex ? "мужской" : "женский");
            text += ", возраст: " + this.age;

            int childCount = this.children.size();
            if (childCount > 0) {
                text += ", дети: " + this.children.get(0).name;

                for (int i = 1; i < childCount; i++) {
                    Human child = this.children.get(i);
                    text += ", " + child.name;
                }
            }
            return text;

public static void main(String[] args) {
        Human grandFather1 = new Human("Heiko",true,83);
        Human grandFather2 = new Human("Hans",true,81);
        ArrayList<Human> grandFathers = new ArrayList<>(); grandFathers.add(grandFather1); grandFathers.add(grandFather2);

        Human kind1 = new Human("Mariya",false,4);
        Human kind2 = new Human("Sem",true,3);
        Human kind3 = new Human("Tomy",true,9);
        ArrayList<Human> childs = new ArrayList<>(); childs.add(kind1); childs.add(kind2);childs.add(kind3);
        childs.add(new Human("krlek",true,34));