diff --git a/plugins/stoa/lib/stoa_plugin/person_api.rb b/plugins/stoa/lib/stoa_plugin/person_api.rb
index 6c1324f..0f13018 100644
--- a/plugins/stoa/lib/stoa_plugin/person_api.rb
+++ b/plugins/stoa/lib/stoa_plugin/person_api.rb
@@ -20,7 +20,7 @@ class StoaPlugin::PersonApi < Noosfero::FieldsDecorator
   end
 
   def birth_date
-    object.birth_date.strftime('%F')
+    object.birth_date.present? ? object.birth_date.strftime('%F') : nil
   end
 
   def image_base64
--
libgit2 0.21.2