diff --git a/clkhash/randomnames.py b/clkhash/randomnames.py
index 209cfb9e..5b9aa185 100644
--- a/clkhash/randomnames.py
+++ b/clkhash/randomnames.py
@@ -94,6 +94,10 @@ def __init__(self, n):
 
         self.names = [person for person in self.generate_random_person(n)]
 
+        self.all_male_first_names = None
+        self.all_female_first_names = None
+        self.all_last_names = None
+
     @property
     def schema_types(self):
         # type: () -> Sequence[FieldSpec]