how to reference a child gameobject unity

1    private void Start()
2    {
3        parentObject = GameObject.Find("Parent");// The name of the parent object
4        childObject = parentObject.transform.GetChild(0).gameObject; // the parent index (starting from 0)
5    }

1//For unity engine
2GameObject.transform.GetChild(The child index).transform;

1		// spawns object
2        objToSpawn = new GameObject("Start");
3
4        // add Components
5        objToSpawn.AddComponent<Rigidbody>();
6        objToSpawn.AddComponent<MeshFilter>();
7        objToSpawn.AddComponent<BoxCollider>();
8        objToSpawn.AddComponent<MeshRenderer>();
9
10        // sets the obj's parent to the obj that the script is applied to
11        objToSpawn.transform.SetParent(this.transform);

1Transform[] transforms = this.GetComponentsInChildren<Transform>();
2 
3 foreach(Transform t in transforms)
4 {
5     if (t.gameObject.name == "Child")
6     {
7         Debug.Log ("Found " + t);
8     }
9 }