也许有更好的方法可以做到这一点，但这应该是可行的：

 $the_terms = get_terms( \'category\', \'child_of=<replace with parent id>\' );

 $included_terms = array(\'<replace with parent id>\' );

 if( $the_terms )
 {
      foreach( $the_terms as $the_term )
           $included_terms[] = $the_term->term_id;
 }

 sort( $included_terms );

 wp_list_categories(
      \'include\' => $included_terms
 );