random issue

using UnityEngine;
using System.Collections;


public class Generator1 : MonoBehaviour {

    public GameObject[] obj;
    public float MinTime, MaxTime;

    void Start()
    {
        if (Puntuation.getPoints() >= 20)
        {
            Generate();
        }//outer
    }


    void Generate()
    {
        Object r = obj[Random.Range(0, obj.Length)];
        Instantiate( r , transform.position, Quaternion.identity);
        Invoke("Generate", Random.Range(MinTime, MaxTime));
    }//generar

}//class