Index: wp-includes/query.php
===================================================================
--- wp-includes/query.php	(revision 15432)
+++ wp-includes/query.php	(working copy)
@@ -188,17 +188,20 @@
 
 	if ( empty($category) )
 		return true;
-
+		
 	$cat_obj = $wp_query->get_queried_object();
 
 	$category = (array) $category;
 
-	if ( in_array( $cat_obj->term_id, $category ) )
-		return true;
-	elseif ( in_array( $cat_obj->name, $category ) )
-		return true;
-	elseif ( in_array( $cat_obj->slug, $category ) )
-		return true;
+	foreach($category as $cat){
+		if ( is_numeric($cat) )
+			if ( absint($cat) == $cat_obj->term_id )
+				return true;
+		if ( $cat == $cat_obj->name )
+			return true;
+		if ( $cat == $cat_obj->slug )
+			return true;
+	}
 
 	return false;
 }