gender select error validation

[brown2005]

<legend><span>Gender</span></legend><div><input type="radio" id="male" name="gender" value="male"><label for="male">Male</label></div><div><input type="radio" id="female" name="gender" value="female"> <label for="female">Female</label></div>
<p class="error hidden" id="err_gender"></p>

 

and how would I change this code below to work on the above

 

if ( empty ( $_POST [ 'male' ] ) && empty ( $_POST [ 'female' ] ) )

{

$errors [ 'gender' ] [] = "Please enter your gender\n";

}

[abazoskib]

if ( empty ( $_POST [ 'gender' ] ) )
{
   $errors [ 'gender' ] [] = "Please enter your gender\n";
}