diff --git a/features/factory_girl_steps.feature b/features/factory_girl_steps.feature
index 84e8eb9..edf6ea0 100644
--- a/features/factory_girl_steps.feature
+++ b/features/factory_girl_steps.feature
@@ -190,3 +190,11 @@ Feature: Use step definitions generated by factories
     Then I should find the following for the last user:
       | id  | name |
       | 123 | Joe  |
+
+  Scenario: pass a factory girl table as an argument and modify it
+    Given these super users exist:
+      | id  | Name |
+      | 123 | Joe  |
+    Then I should find the following for the last user:
+      | id  | name | admin |
+      | 123 | Joe  | true  |
diff --git a/features/step_definitions/factory_girl_steps.rb b/features/step_definitions/factory_girl_steps.rb
index 5bb03f0..f03c151 100644
--- a/features/step_definitions/factory_girl_steps.rb
+++ b/features/step_definitions/factory_girl_steps.rb
@@ -16,3 +16,10 @@ end
 When /^I create a "([^"]*)" instance from Factory Girl$/ do |factory_name|
   FactoryGirl.create(factory_name)
 end
+
+Given /^these super users exist:$/ do |table|
+  headers = table.headers + ["admin"]
+  rows    = table.rows.map { |row| row + [true] }
+  new_table = Cucumber::Ast::Table.new([headers] + rows)
+  Given %{the following person exists:}, new_table
+end
diff --git a/lib/factory_girl/step_definitions.rb b/lib/factory_girl/step_definitions.rb
index c3386bf..226e6c1 100644
--- a/lib/factory_girl/step_definitions.rb
+++ b/lib/factory_girl/step_definitions.rb
@@ -21,7 +21,7 @@ module FactoryGirlStepHelpers
     private
 
     def process_key_value(key, value)
-      [key.downcase.gsub(' ', '_').to_sym, value.strip]
+      [key.downcase.gsub(' ', '_').to_sym, value.to_s.strip]
     end
 
     class AssociationManager