How to create radio button element in Zend Framework?

$gender = new Zend_Form_Element_Radio('gender');
$gender->setLabel('Gender')
->setRequired(true)->setErrorMessages(array(
'isEmpty'=>'You should must select your gender.'
))
->setRequired(true)
->addMultiOptions(array(
'male' => 'Male',
'female' => 'Female'
));