You mean like:
<?php if ( is_category('1') || is_category('2') || is_category('3') ) {
Thanks Michael but no joy with that.
I think my problem is that I am trying to call a sub (child) category separate from a parent category:
Parent Category 1
<?php if ( is_category('2') ) {
echo '<ul class="show" id="childcat1">';
} else {
echo '<ul class="hide" id="childcat1">';
}
?>
<?php
$posts_li = new WP_Query(array('category__and'=>array(2),'showposts'=>-1,'orderby'=>title,'order'=>ASC));
?>
<?php while( $posts_li->have_posts() ) : $posts_li->the_post(); ?>
<li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
<?php endwhile; ?>
etc
and repeat for each child category.