Duplicating post titles in category

Attempting to dynamically output post titles from a child category but on the category page itself it’s outputting them twice, can anyone tell me why? Thanks.

<?php
$IDOutsideLoop = $post->ID;
 while( have_posts() ) {
   the_post();
   foreach( ( get_the_category() ) as $category )
      $my_query = new WP_Query('category_name=' . $category->category_nicename . '&orderby=title&order=asc&showposts=100');
     if( $my_query ) {
        while ( $my_query->have_posts() ) {
          $my_query->the_post(); ?>
          <li<?php print ( is_single() && $IDOutsideLoop == $post->ID ) ? ' class="test"' : ''; ?>>
          <a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>"><?php the_title(); ?></a></li>
            <?php
           }
        }
 } ?>