PHP OOP：迭代从类创建的所有对象

Question

I want to create a <select> field from all Gender objects. Is there a way to iterate over all the objects created from the class of Gender?

class Gender {

    public static $counter = 0;
    public $id;
    public $gender;

    public function __construct($gender){
        Gender::$counter++;
        $this->id = Gender::$counter;
        $this->gender = $gender;
    }

}

// Objects
$gender_male = new Gender('Male');
$gender_female = new Gender('Female');

Answer 1

I understand now that it's an extreme overkill to use a class but for the sake of knowing how it's done, here's the new code (based on all your comments):

class Gender {

    public static $counter = 0;
    public static $genders = array();

    public function __construct($gender){
        // Here it is
        Gender::$genders[++Gender::$counter] = $gender;
    }

}

// Objects
$gender_male = new Gender('Male');
$gender_female = new Gender('Female');

It's a group achievement in its own way but I think I'll switch to arrays instead. :-)