diff --git a/app/models/form/lettings/questions/person_sex_registered_at_birth.rb b/app/models/form/lettings/questions/person_sex_registered_at_birth.rb
index b549885b1..be99fcd1e 100644
--- a/app/models/form/lettings/questions/person_sex_registered_at_birth.rb
+++ b/app/models/form/lettings/questions/person_sex_registered_at_birth.rb
@@ -18,6 +18,6 @@ class Form::Lettings::Questions::PersonSexRegisteredAtBirth < ::Form::Question
   def question_number
     base_question_number = 29
 
-    base_question_number + (5 * @person_index)
+    base_question_number + (form.person_question_count * @person_index)
   end
 end