Index: includes/form.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/form.inc,v
retrieving revision 1.509
diff -u -p -b -r1.509 form.inc
--- includes/form.inc	13 Nov 2010 14:04:08 -0000	1.509
+++ includes/form.inc	14 Nov 2010 05:35:30 -0000
@@ -2600,7 +2600,7 @@ function theme_radio($variables) {
   $element['#attributes']['type'] = 'radio';
   element_set_attributes($element, array('id', 'name', '#return_value' => 'value'));
 
-  if (isset($element['#return_value']) && check_plain($element['#value']) == $element['#return_value']) {
+  if (isset($element['#return_value']) && $element['#value'] !== FALSE && $element['#value'] == $element['#return_value']) {
     $element['#attributes']['checked'] = 'checked';
   }
   _form_set_class($element, array('form-radio'));
@@ -2819,7 +2819,7 @@ function form_process_radios($element) {
       $element[$key] += array(
         '#type' => 'radio',
         '#title' => $choice,
-        '#return_value' => check_plain($key),
+        '#return_value' => $key,
         '#default_value' => isset($element['#default_value']) ? $element['#default_value'] : NULL,
         '#attributes' => $element['#attributes'],
         '#parents' => $element['#parents'],