php storm не видит переменную

Подскажите пожалуйста, не могу понять почему переменная $gender не определена, в то время когда другие переменные определены таким же способом и при этом видны? https://hostfotos.ru/images/2020/02/15/SNIMOK-EKRANA-2020-02-15-V-11.06.10.png https://hostfotos.ru/images/2020/02/15/SNIMOK-EKRANA-2020-02-15-V-11.05.45.png

MODEL

    public static function checkCityExist($from_city)
    {
        include_once 'config/arrays/citys.php';

        if ($from_city != "" and array_key_exists($from_city, $my_city) == $from_city) {
            return true;
        }
        return false;
    }

    public static function checkVars($password, $name, $gender, $birth_day, $birth_month, $birth_year, $height, $weight, $about){

        if ($password != '' and $name != '' and $gender = '' and $birth_day != '' and $birth_month != '' and $birth_year != '' and $height !='' and $weight != '' and $about != '') {

            return true;
        }
        return false;

    }

CONTROLLER

include_once(ROOT . '/models/User.php');

class RegController
{

    public function actionIndex()
    {

        if (isset($_POST['password']) and isset($_POST['name']) and isset($_POST['name']) and isset($_POST['gender']) and isset($_POST['birth_day']) and isset($_POST['birth_month']) and isset($_POST['birth_year']) and isset($_POST['height']) and isset($_POST['weight']) and isset($_POST['about'])) {

            $password = $_POST['password'];
            $name = $_POST['name'];
            $gender = $_POST['gender'];
            $birth_day = $_POST['birth_day'];
            $birth_month = $_POST['birth_month'];
            $birth_year = $_POST['birth_year'];
            $height = $_POST['height'];
            $weight = $_POST['weight'];
            $about = $_POST['about'];

            $errors = false;

            if (!User::checkVars($password, $name, $gender, $birth_day, $birth_month, $birth_year, $height, $weight, $about)) {
                $errors = "*Не заполнены обязательные поля!\n";
            }

            if ($errors == false) {

                header("Location: /saved");
                exit;
            }
        }

        require_once(ROOT . '/views/users/reg.php');

        return true;
    }

}