I'll try to respond to everyone's question in this post. I believe concerning the creation as follows:
God created all that is created, we are given this at Gen. 1.1 onward. In the beginning God created the heavens and the earth.
Lucifer was a created angel. In the original creation at Gen. 1.1. there was not the confusion of sin in the universe. Later it was found in the heart of Lucifer and was pride. This follows I think from Is. 24 and Ez. 14 or maybe vice versa. I don't remember, nevertheless, he was cast out and those angels he took with him, which I believe is seen in Rev. 13.
Now back to Genesis 1.2: And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters.
The first part is a result of the judgement of Lucifer and the fallen angels. Sin now thrives in the universe.
vs. 3: And God said, Let there be light: and there was light.
Here begins the work of creation that forms the cattle, beasts etc and man. Separates the atmosphere from the firmament etc.
On the sixth day man was created, sinless, but not HOLY, nor in righteousness as he will be in the resurrection. He was in a righteousness I call 'original' because he was made without sin. But this was in the universe and through Lucifer, now Satan, was in the world, even the Garden of Eden.
Man by his (then) free-will chose to become a partaker of this sin and thus is the sinfulness of man.
Concerning babies.
This is a much more difficult question. The best example in scripture is that of the child of David and Bathsheba. Not only does this child have the full nature of man, he can rightly agree with David that he too was formed in iniquity (as a direct result of the sin of David). Yet David has a faith which when the child is alive he fasts and prays, but once the child dies he is resolved in his faith that he cannot bring the child back to him, but can go to the child.
The problem here is two fold, as I see it. First, the child obviously did not live long enough to add to his sin nature his own personal sins as we have and countless others.
Next, if not careful here we can fall into the false belief held among Catholics of being able to pray someone into salvation once they are passed away. I can see how this episode would encourage that thought and cause the formulation of a doctrine around it.
What is at the core of the question "What of infants dying before reaching the age of accountability?"
I believe it is that our human emotions desire the comfort of knowing that though we have been deprived of the joy of this person, our child, etc. we will be able to "join" that child in the next world.
The problem with this is it is built not entirely upon the Word of God, but draws its strength from human emotion and desire. Did the child possess a sin nature, sure, all born of man and woman do. Is the child received into the arms of Christ at death, this is what is taught, but I believe it is so taught from the wrong motivations. If it is true, it adds strength to the Primitive Baptist belief that not all will hear the Gospel, certainly the infant never heard a man preach the Gospel, even in cases where they live two or three years, to where they are able to understand it. However, this does not prohibit the regeneration of the infant by the Holy Spirit, who, as He did with Abraham, does also with the infant, and preaching the Gospel becomes the ministry of the Holy Spirit. The child then, upon death has been regenerated by the Spirit and not one effort at evangelism from human means has occurred. We must believe this if we are going to use this as a comfort to those parents who have suffered this loss.
Again, the problem becomes one of where the source of our conviction lays. Is it in the seat of the heart of man, or is it from the Fountain of Eternal Truth?
This question is deeper than what I can fully answer. But we must grasp onto the Truth that is in God and be done with what we envision as equality or human rights. If all who die in infancy are saved, then the Devil is only defeating himself by encouraging abortions

. I admit this is the doctrine which I have always heard, but at the same time I hear it said that men are not elected, or that they must hear the Gospel preached, that this is now through the instrumentality of man, but none of this is true to the Word of God, what is true?, that preaching of the Gospel, regeneration, is all a full and complete work of the Holy Spirit, that it will be accomplished with or without man's involvement.
Then to deny the sin nature to infants until they reach an age to where they are accountable presents another problem, only God knows this age. Further, the problem, and much greater one at that IMO, is that we produce a scenario where it may be possible for one to be born (remember not possessing the sin nature), who is capable of living a sinless life by choice and thus make the cross of no effect. If one can do it why not others, then we have a blunder on the part of God for 'so loving the world that he gave his only begotten son, that whosoever believeth on him should not perish but have everlasting life' this blunder is evident because if just one is able to be saved by choice of living a sinless life, then all would and there is no real need for a Savior, but man becomes his own redeemer.
Then the argument may be heard that noone can live a sinless life. But I beg to differ, in truth, if they are born not weighed down with the sin nature, then once they come to the age of accountability they choose to sin, from where did this choice originate? If you say they sin before they realize it, then you cut your own throat, because if they know not the consequence of their actions they have not obtained the secret age of accountability.
The truth must ultimately lie with God. I agree with Scripture, let everyman be a liar. And again, that the mouths of men may be stopped. Amen.
God Bless.
Bro. Dallas