How to wait scene to load if using IEnumerator Start()?

Hi, I have to use WWW to init my scene, so it looks like this.

IEnumerator Start () { yield return StartCoroutine (InitScene ()); //including WWW calls }

Unfortunately, lots of GameObjects were created in InitScene(), so what I see is the scene show up when GameObjects are not ready, then it begins to instantiate them 1 by 1, for sure this isn't what player want to see.

Is there anyway to make it act like Void Start()? Just let the scene show up after Start() had been completely loaded?

Thank you!