How do mogwai's breed?

In gremlins when gizmo gets wet he multiplies but all his "offspring"
are evil, stupid and rude. Is this the only way mogwai's reproduce or
are the "offspring" just a defense mechanism or something?

If it is how they reproduce how come none of the mogwai gizmo gives
birth to are nice and cuddly like him? Did the old asian man have to
train him to be like that or something?