Index: wp-includes/taxonomy.php
===================================================================
--- wp-includes/taxonomy.php	(revision 18157)
+++ wp-includes/taxonomy.php	(working copy)
@@ -1454,7 +1454,7 @@
 
 	$term = trim( stripslashes( $term ) );
 
-	if ( '' === $slug = sanitize_title($term) )
+	if ( '' === $slug = $term )
 		return 0;
 
 	$where = 't.slug = %s';