diff --git a/backend/app/Http/Controllers/Api/FatherRelationsController.php b/backend/app/Http/Controllers/Api/FatherRelationsController.php
index f294e968..f5b87bbf 100644
--- a/backend/app/Http/Controllers/Api/FatherRelationsController.php
+++ b/backend/app/Http/Controllers/Api/FatherRelationsController.php
@@ -44,7 +44,7 @@ class FatherRelationsController extends Controller {
         }
 
         $validate = Validator::make($r->all(), [
-            'identity' => 'required|max:20|alpha_num',
+            'identity' => 'required|max:20|numeric',
         ]);
 
         if ($validate->fails()) {