Taxonomy terms produce invalid html code

This is what I get when I use a taxonomy to tag my blog entries:

<span class="terms">
  <ul class="links inline">
    <li class="first taxonomy_term_69">
      <a href="/taxonomy/term/69" rel="tag" title="" class="taxonomy_term_69">Football</a>
    </li>
    <li class="last taxonomy_term_68">
      <a href="/taxonomy/term/68" rel="tag" title="" class="taxonomy_term_68">On tour</a>
    </li>
  </ul>
</span>

Unfortunately it is no valid HTML to put a "ul" inside a "span". Any ideas how to avoid that?