Create a child contract from parent contract via remix

Question

I was trying to create a new contract from another one like this:

pragma solidity ^0.4.8;

contract Child {
    address public owner;

    function Child() public {
        owner = msg.sender;
    }
}

contract Parent {
    address owner;

    event NewChildCreated(address childAddress, address creator);

    function Parent() public {
        owner = msg.sender;
    }

    function createChild() public {
        Child child = new Child();
        NewChildCreated(address(child), child.owner());
    }
}

So in remix I called createChild() from the Parent and there is a log with the address of that newly-created Child contract (e.g. 0x1234).

However, when I copied that address and created a Child instance based on that address (0x1234) in remix, I was not able to access the owner property of it. I was getting this error: call to Child.owner errored: Cannot read property 'length' of undefined.

Am I creating the child contract wrongly? Why I cannot refer to the newly-created Child contract?