rails 3.2 question/answer with a through table

[Me]

I have a person has many questions through person_questions.  I have an extra column in the join table for the answer.  The section below works for a new submit but when I edit I get 3 each with the first 2 of each selected tand the third not so I get 6 check boxes some selected some not.  Is there a way to get this  to work properly os just the questions in the db show up once each with the appropriate ones checked?

The questions are in the db.

Questions: <br/>

        <% Question.all.each do |question| %>

          <%= f.fields_for :person_questions do |pregunta| %>

            <%= render 'questions/question_type', :pregunta => pregunta, :question => question, :f => f %>

          <% end %>

        <% end %>

Partial:

<div class="control-group">

  <%= pregunta.label question.name, (question.label_text unless question.label_text.nil?), :class => 'control-label' %>

  <div class="controls">

    <% if question.data_type == 'select' %>

      <%= pregunta.send(question.data_type, :answer, question.to_select,:class => "#{question.data_type}")  %>

      <%= pregunta.hidden_field :question_id, :value => question.id , :class => "#{question.data_type}" %>

    <% else %>

      <%= pregunta.send(question.data_type, :answer, :class => "#{question.data_type}" ) %>

      <%= pregunta.hidden_field :question_id, :value => question.id , :class => "#{question.data_type}" %>

    <% end %>

  </div>

</div>