<% form_for @person do |person_form| %>

  <%= person_form.label :name %>
  <%= person_form.text_field :name %>

  <% person_form.fields_for :children do |child_form| %>

    <%= child_form.label :name %>
    <%= child_form.text_field :name %>

    <% unless child_form.object.new_record? %>
      <%= child_form.check_box '_delete' %>
      <%= child_form.label '_delete', 'Remove' %>
    <% end %>

  <% end %>

  <%= submit_tag %>
<% end %>