package Person;
use Moose;
use Moose::Util::TypeConstraints;
subtype 'Gender' => as 'Str' => where { /^(female|male)$/ };
has sex     => ( is => 'rw', isa => 'Gender' );

package Person;
use Moose;
use Moose::Util::TypeConstraints;
enum Gender => qw(female male);
has sex     => ( is => 'rw', isa => 'Gender' );