Transform.localPosition Scripting Problem.

Hello. I have created a script that, when a certain object is touched, moves the parents selected and moves them along the Z axis. The script is

  using UnityEngine;
  using System.Collections;
  
  public class Expands : MonoBehaviour {
      
      public Transform parent;
      public float expandAmount = 1.5f;
      public float localPosition = 1f;
      
      void OnMouseDown()
      {
          parent.localScale *=expandAmount;
          parent.localPosition *= localPosition;
          for(int i =0;i<parent.childCount;i++)
          {
              parent.GetChild(i).localScale =new Vector3(1/parent.localScale.x,1/parent.localScale.y, 1/parent.localScale.z);
              parent.GetChild(i).localPosition = new Vector3(0, 0, -1f);
          }
      }
  }
  

The script does move the objects down the Z axis as I wanted, but it also changes the Y and X positions to 0, which is not what I want. How can the script be modified so that the Y and X positions do not change. This game is 2D and for the Android. All help is appreciated.