title: validates_presence_of + :message shows the name of the field
body: <p>I'm creating a Rails app, and I have a model called <code>User</code>. In this model I have a boolean value called <code>isagirl</code>. A user must specify if it is a girl or not, which is done by two radio buttons. In my model I have this:</p>
  
  <pre><code>validates_presence_of :isagirl, :message =&gt; "You must be either a Boy or a Girl. If not, please contact us."
  </code></pre>
  
  <p>However, when I don't specify a sex, I'm seeing this:</p>
  
  <blockquote>
    <p>Isagirl You must be either a Boy or a Girl.</p>
  </blockquote>
  
  <p>as an error message. The problem is that 'Isagirl' must not be there in the error message. How can I disable that? And no, using CSS to hide it is no option.</p>
  
  <p>Thanks</p>