Will check if given post_id has children in given post_type

has_children

/**
 * Has Children
 **/
function has_children( $post_id, $post_type ) {
	global $wpdb;
		
	$querystr = "SELECT $wpdb->posts.ID FROM $wpdb->posts WHERE $wpdb->posts.post_type = '$post_type' AND $wpdb->posts.post_parent = '$post_id' LIMIT 1";

	$results = $wpdb->get_results( $querystr, ARRAY_N );

	if ( is_numeric( $results[0][0] ) AND $results[0][0] > 0 )
		return true;
	else
		return false;
		
} // end function has_children