diff --git a/src/Symfony/Component/Form/DateField.php b/src/Symfony/Component/Form/DateField.php
index 3330bad81f..f08c4733e9 100644
--- a/src/Symfony/Component/Form/DateField.php
+++ b/src/Symfony/Component/Form/DateField.php
@@ -89,6 +89,19 @@ class DateField extends HybridField
      */
     protected $formatter;
 
+    /**
+     * {@inheritDoc}
+     */
+    public function __construct($key, array $options = array())
+    {
+        // Override parent option
+        // \DateTime objects are never edited by reference, because
+        // we treat them like value objects
+        $this->addOption('by_reference', false);
+
+        parent::__construct($key, $options);
+    }
+
     protected function configure()
     {
         $this->addOption('widget', self::CHOICE, self::$widgets);
diff --git a/src/Symfony/Component/Form/DateTimeField.php b/src/Symfony/Component/Form/DateTimeField.php
index 3002b7f2bf..5f9d96ed8d 100644
--- a/src/Symfony/Component/Form/DateTimeField.php
+++ b/src/Symfony/Component/Form/DateTimeField.php
@@ -75,6 +75,19 @@ class DateTimeField extends Form
         TimeField::INPUT,
     );
 
+    /**
+     * {@inheritDoc}
+     */
+    public function __construct($key, array $options = array())
+    {
+        // Override parent option
+        // \DateTime objects are never edited by reference, because
+        // we treat them like value objects
+        $this->addOption('by_reference', false);
+
+        parent::__construct($key, $options);
+    }
+
     protected function configure()
     {
         $this->addOption('date_widget', DateField::CHOICE, self::$dateWidgets);
diff --git a/src/Symfony/Component/Form/Form.php b/src/Symfony/Component/Form/Form.php
index 820772bd1b..6b0886bf82 100644
--- a/src/Symfony/Component/Form/Form.php
+++ b/src/Symfony/Component/Form/Form.php
@@ -93,6 +93,7 @@ class Form extends Field implements \IteratorAggregate, FormInterface
         $this->addOption('virtual', false);
         $this->addOption('validator');
         $this->addOption('context');
+        $this->addOption('by_reference', true);
 
         if (isset($options['validation_groups'])) {
             $options['validation_groups'] = (array)$options['validation_groups'];
@@ -880,6 +881,21 @@ class Form extends Field implements \IteratorAggregate, FormInterface
         }
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    public function writeProperty(&$objectOrArray)
+    {
+        $data = $this->getData();
+
+        // Don't update parent if data is a composite type (object or array)
+        // and "by_reference" option is true, because then we expect that
+        // we are working with a reference to the parent's data
+        if (!(is_object($data) || is_array($data)) || !$this->getOption('by_reference')) {
+            parent::writeProperty($objectOrArray);
+        }
+    }
+
     /**
      * Merges two arrays without reindexing numeric keys.
      *
diff --git a/src/Symfony/Component/Form/TimeField.php b/src/Symfony/Component/Form/TimeField.php
index 3f221db2b4..a8961fe7aa 100644
--- a/src/Symfony/Component/Form/TimeField.php
+++ b/src/Symfony/Component/Form/TimeField.php
@@ -59,6 +59,19 @@ class TimeField extends Form
         self::RAW,
     );
 
+    /**
+     * {@inheritDoc}
+     */
+    public function __construct($key, array $options = array())
+    {
+        // Override parent option
+        // \DateTime objects are never edited by reference, because
+        // we treat them like value objects
+        $this->addOption('by_reference', false);
+
+        parent::__construct($key, $options);
+    }
+
     /**
      * {@inheritDoc}
      */
diff --git a/tests/Symfony/Tests/Component/Form/FormTest.php b/tests/Symfony/Tests/Component/Form/FormTest.php
index 128fd50f64..e23cc3212d 100644
--- a/tests/Symfony/Tests/Component/Form/FormTest.php
+++ b/tests/Symfony/Tests/Component/Form/FormTest.php
@@ -41,6 +41,59 @@ class FormTest_PreconfiguredForm extends Form
     }
 }
 
+// behaves like a form with a value transformer that transforms into
+// a specific format
+class FormTest_FormThatReturns extends Form
+{
+    protected $returnValue;
+
+    public function setReturnValue($returnValue)
+    {
+        $this->returnValue = $returnValue;
+    }
+
+    public function setData($data)
+    {
+    }
+
+    public function getData()
+    {
+        return $this->returnValue;
+    }
+}
+
+class FormTest_AuthorWithoutRefSetter
+{
+    protected $reference;
+
+    protected $referenceCopy;
+
+    public function __construct($reference)
+    {
+        $this->reference = $reference;
+        $this->referenceCopy = $reference;
+    }
+
+    // The returned object should be modified by reference without having
+    // to provide a setReference() method
+    public function getReference()
+    {
+        return $this->reference;
+    }
+
+    // The returned object is a copy, so setReferenceCopy() must be used
+    // to update it
+    public function getReferenceCopy()
+    {
+        return is_object($this->referenceCopy) ? clone $this->referenceCopy : $this->referenceCopy;
+    }
+
+    public function setReferenceCopy($reference)
+    {
+        $this->referenceCopy = $reference;
+    }
+}
+
 class TestSetDataBeforeConfigureForm extends Form
 {
     protected $testCase;
@@ -1130,6 +1183,71 @@ class FormTest extends \PHPUnit_Framework_TestCase
         $form->validateData($context);
     }
 
+    public function testSubformDoesntCallSetters()
+    {
+        $author = new FormTest_AuthorWithoutRefSetter(new Author());
+
+        $form = new Form('author', array('validator' => $this->createMockValidator()));
+        $form->setData($author);
+        $refForm = new Form('reference');
+        $refForm->add(new TestField('firstName'));
+        $form->add($refForm);
+
+        $form->bind($this->createPostRequest(array(
+            'author' => array(
+                // reference has a getter, but not setter
+                'reference' => array(
+                    'firstName' => 'Foo',
+                )
+            )
+        )));
+
+        $this->assertEquals('Foo', $author->getReference()->firstName);
+    }
+
+    public function testSubformCallsSettersIfByReferenceIsFalse()
+    {
+        $author = new FormTest_AuthorWithoutRefSetter(new Author());
+
+        $form = new Form('author', array('validator' => $this->createMockValidator()));
+        $form->setData($author);
+        $refForm = new Form('referenceCopy', array('by_reference' => false));
+        $refForm->add(new TestField('firstName'));
+        $form->add($refForm);
+
+        $form->bind($this->createPostRequest(array(
+            'author' => array(
+                // referenceCopy has a getter that returns a copy
+                'referenceCopy' => array(
+                    'firstName' => 'Foo',
+                )
+            )
+        )));
+
+        // firstName can only be updated if setReferenceCopy() was called
+        $this->assertEquals('Foo', $author->getReferenceCopy()->firstName);
+    }
+
+    public function testSubformCallsSettersIfReferenceIsScalar()
+    {
+        $author = new FormTest_AuthorWithoutRefSetter('scalar');
+
+        $form = new Form('author', array('validator' => $this->createMockValidator()));
+        $form->setData($author);
+        $refForm = new FormTest_FormThatReturns('referenceCopy');
+        $refForm->setReturnValue('foobar');
+        $form->add($refForm);
+
+        $form->bind($this->createPostRequest(array(
+            'author' => array(
+                'referenceCopy' => array(), // doesn't matter actually
+            )
+        )));
+
+        // firstName can only be updated if setReferenceCopy() was called
+        $this->assertEquals('foobar', $author->getReferenceCopy());
+    }
+
     /**
      * Create a group containing two fields, "visibleField" and "hiddenField"
      *