phMailer 1.5 Control radio button

radio button control?
make control?

PHP Code:

if(theform.sex.value=="") {
        error+="You did not enter your name\n";
    }

<?=stripslashes(htmlspecialchars($sex));?>

<p>Male<input type="radio" value="male" name="sex"> Female<input type="radio" value="female" name="sex">