Vector of unique_ptr member

I have the following:

typedef std::vector<std::unique_ptr<Node>> NodeList;
class Node
{
 public:
    Node();
    Node(NodeType _type);
    virtual ~Node();

    NodeType getNodeType() const;
    Node const* getParentNode() const;
    // I want a member function to allow acces to the
    // childNodes vector
    bool hasChildNodes() const;

    void setParent(Node* node);
    void appendChild(std::unique_ptr<Node> node);
protected:
    NodeType _nodeType;
    Node* parentNode;
    NodeList childNodes;
};

I want the user of the class to have access to the childNodes (read or read and write). How can I achieve that?