checkboxes and radios doesn't display with forms api

Hi I'm using Drupal 6.18 I'm developing a module with forms.But i'm experiencing a problem with the display part of checkboxes and radio buttons.
Both of them do not display in my form i used the follwing code from the resource http://api.drupal.org/api/drupal/developer--topics--forms_api_reference....

For Radios I used

$form['radio'] = array(
  '#type' => 'radios',
  '#title' => t('Gender'),
  '#options' => array(t('Male'), t('Female')),
);

For checkboxes :

$form['chck'] = array(
  '#type' => 'checkboxes',
  '#title' => t('Default options'),
  '#options' => array(
    'status' => t('test1'),
    'moderate' => t('test2'),
    'promote' => t('test3'),
    'sticky' => t('test4'),
    'revision' => t('test5'),
  ),
  '#description' => t('This is a test.'),
);