RewriteEngine On
RewriteBase /

# Allow pretty URLs: /young/hex-encoded-email
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^young/([0-9a-fA-F]+)$ young.php?email=$1 [L,QSA]

# Handle root requests
RewriteRule ^$ young.php [L]