How can I fetch() related models in parse() with Backbone.js?

Consider we are working with an API that exposes two objects, Parent and Child, where a Parent has many Child objects. The server represents this relationship in representations of Parent objects as a list of IDs of Child objects:

{
    ...
    children: [1, 2, 5, 19, ...],
    ...
}

Assuming we can't change the server's response, how can we fetch Child objects when fetching Parents object using Backbone.js? Roughly, the following code is what I want, but it does not work because child.fetch() is asynchronous:

var Child = Backbone.Model.extend({
    url: function() {
        return "/children/" + this.model.get('id');
    }
});

var Parent = Backbone.Model.extend({
    parse: function(response) {
        response.children = _.map(response.children, function(id) {
            var child = Child({id: id});
            child.fetch();  // Ideally, this would be synchronous
            return child.attributes;
        });
        return response;
    },
    url: function() {
        return "/parents/" + this.model.get('id');
    }
});

var parent = new Parent({id: 0});
Parent.fetch();

Without this piece, I cannot render my views, which has Child views nested within Parent views:

var ParentView = Backbone.View.extend({
    initialize: function() {
        this.childViews = _.map(this.model.get('children'), function(child) {
            return ChildView({model: child});
        });
    },

    template: _.template($('#parent-template').html()),

    render: function() {
        this.$el.html(this.template(this.model.toJSON()));
        _.each(this.childViews, function(view) {
           this.$el.append(view.render().el);
        });
        return this;
    }
});

var ChildView = Backbone.View.extend({
    template: _.template($('#parent-template').html()),

    render: function() {
        this.$el.html(this.template(this.model.toJSON()));
        return this;
    }
});

Several solutions have occurred to me so far, but none of them work without drawbacks:

• 
  

  Move the fetch() logic into initialize(), but this runs into all the same problems, plus leaving the model in an inconsistent state between fetch() and initialize().

  
  


• 
  

  fetch() (and render()) the Child objects in Parent.render(), but this contaminates rendering with initialization logic.