Repeater’s already given you the proper answer to your question (“how to delete Object Memory of CMyChild type”), but you could also wonder whether you need pointers or not («How could I get rid of my raw pointers?»).
Firstly, you should consider standard containers already take care of ‘keeping alive’ or destroying the objects you push into them, so there could be no need to explicitly allocate those in the heap, since they will live until the container lives.
Secondly, you could replace raw pointers with smart pointers.