Store radio button value in PHP variable

<form method="post">
 <input type="radio" name="gender" value="male">Male
 <input type="radio" name="gender" value="female">Female
 <input type="submit" name="submit" value="Get Value">
</form>
<?php
if(isset($_POST['submit'])){
// always same name with multiple radio button
echo $radioData = $_POST['gender'];
}
?>