Like I said, it doesn't solve the 'Amazon baby mama' problem but it does open up several story telling possibilities; it makes Diana's birth all the more significant and raises the question of what the significance of having a child in a society that has no need to procreate. The Amazons were given powerful bodies by the Goddesses, their numbers can be replenished via the Well of Souls, so I can imagine the Goddesses also being like 'childbirth? unnecessary, lets just take that feature out'.