php redirect based on url variable

Question could use a little bit of a better explanation. Do you mean that someone is going to http://www.yoursite.com/yourscript.php?student%20gender=male and you want them to be redirected to http://www.one.com?

If this is the case, PHP has a built in variable known as $_GET which stores the values listed after a ? in a URL. So in the above example, we'd see:

$_GET['student gender'] = male;

You can use this to access any number of parameters separated by &

So the URL http://www.site.com/index.php?val1=a&val2=b&val3=c would give us:

$_GET['val1'] = a;
$_GET['val2'] = b;
$_GET['val3'] = c;

After this, to do a redirect in PHP the easiest way is to send a Location: header. This is done like so:

<?php
header("Location: www.newsite.com");
?>

Combining this with our $_GET variable and some simple logic:

<?php
    if($_GET['student gender'] == 'male'){
        header("Location: www.one.com");
        die();
    } else {
        header("Location: www.two.com");
        die();
    }
?>

$var = $_GET['yourvar'];

if($var == 'one'){
    header("Location: http://www.one.com/");
}else if ($var == 'two'){
    header("Location: http://www.two.com/");
}

then do http://www.yoururl.com?yourvar=one

You also have to make sure you look at the security aspects here, the best way yo accomplish this is

$gender = isset($_REQUEST['gender']) ? $_REQUEST['gender'] : false;

switch($gender)
{
    default: //The default action
        //Send back to the gender select form
    break;

    case 'male':
        //Send to male site!
    break;

    case 'female':
        //Send to female site!
    break;
}

This should be sufficient, but please never use $_X['?'] in functions that execute either shell or database queries without sanitation.

Note: _X being (GET,POST,REQUEST,FILES)