If we assume God exists then yes he would know - because if he didn't know then he wouldn't be God.Does He indeed not know?
Thus God, if he exists, does know sex and reproduction - by definition of being omniscient - and thus would be fit to dictate its laws (if the accusation of "not knowing" was the only reason for God not to be fit).
i.e. with regard God the question is meaningless - simply because God, by definition, does know.
This is simply a logical conclusion following the assumption of God existing and being omniscient.