Insert current userId in DB with INSERT INTO

I'm using MVC php model to build my web site but I get an issue trying to insert current userId from one table to another table (foreign key).

I'm using MySQL last version on ubuntu.

You can see my table below where I want to set the foreign key.

My code:

private function insert() {
    $sql = "INSERT INTO ".self::TABLE_NAME." (last_name_par_enfant, first_name_par_enfant, date_naissance_par_enfant, sexeEnfant, medecin_traitant_par, scolariseEnfantPar, commentaire, date_inserted, idfamily)
            VALUES (
              :last_name_par_enfant,
              :first_name_par_enfant,
              :date_naissance_par_enfant,
              :sexeEnfant,
              :medecin_traitant_par,
              :scolariseEnfantPar,
              :commentaire,
              NOW()
              :idfamily)";

    $pdoStatement = Database::getPDO()->prepare($sql);

    $pdoStatement->bindValue(':last_name_par_enfant', $this->last_name_par_enfant, PDO::PARAM_STR);
    $pdoStatement->bindValue(':first_name_par_enfant', $this->first_name_par_enfant, PDO::PARAM_STR);
    $pdoStatement->bindValue(':date_naissance_par_enfant', $this->date_naissance_par_enfant, PDO::PARAM_STR);
    $pdoStatement->bindValue(':sexeEnfant', $this->sexeEnfant, PDO::PARAM_STR);
    $pdoStatement->bindValue(':medecin_traitant_par', $this->medecin_traitant_par, PDO::PARAM_STR);

    $pdoStatement->bindValue(':scolariseEnfantPar', $this->scolariseEnfantPar, PDO::PARAM_STR);
    $pdoStatement->bindValue(':commentaire', $this->commentaire, PDO::PARAM_STR);
    $pdoStatement->bindValue(':idfamily', $idfamily, PDO::PARAM_INT);
    $affectedRows = $pdoStatement->execute();

    return $affectedRows;
}