function _apci_api_user_create($firstname, $lastname, $email, $gender, $birthday, $password = NULL) {
  $account = array(
    'mail'              => $email,
    'field_firstname'   => array(array('value' => $firstname)),
    'field_lastname'    => array(array('value' => $lastname)),
    'field_user_gender' => array(array('value' => (strtolower($gender) == 'm') ? 1 : 2)),
    'field_birth_date'  => array(array('value' => array(
      'month'  => $birthday['month'],
      'hour'   => '0',
      'minute' => '0',
      'second' => '0',
      'day'    => $birthday['day'],
      'year'   => $birthday['year'],
    ))),
    'pass'             => $password,
    // Send welcome email.
    // 'notify'           => 1,
    // Force password change on first login.
    // 'force_password_change' => '1',
  );
  module_load_include('inc', 'user', 'user.pages');

  // register a new user
  $form_state['values'] = $account;
  $form_state['values']['pass'] = array(
    'pass1' => $account['pass'],
    'pass2' => $account['pass'],
  );
  $form_state['values']['op'] = t('Create new account');

  // Use anonymous to register users.
  global $user;
  $user_logged = $user;
  $user = drupal_anonymous_user();
  // execute the register form
  drupal_execute('user_register', $form_state);
  $user = $user_logged;
  // Error if needed.
  if ($errors = form_get_errors()) {
    return services_error(implode(" ", $errors), 406, array('form_errors' => $errors));
  } else {
    $user2 = array('uid' => $form_state['user']->uid);
    if ($uri = services_resource_uri(array('user', $user2['uid']))) {
      $user2['uri'] = $uri;
    }
    $user = $user2;
  }
  $user = $form_state['user'];
  uuid_user('load', $edit, $user, NULL);
  return _apci_api_user_retrieve($user->uuid, '*');
}