I believe that infants and young children are innocent and that they will be with God. They will not be in hell. To me, this seems rather obvious, but the question had been confused by one of the most unfortunate of false doctrines–one which is rather common in Christian groups. For this reason, I must respond the the false teaching known as Original Sin.
First, let me show you why I believe that children are going to be with God. Ezekiel 18:19-20 (and check out the context please) teaches that each person is responsible before God only for their own sin and not for the sins of others. Unborn infants are certainly not guilty of sin. Neither are small children. They are innocent. I suppose someone will ask whether it is not a sin for a two year old to say "no" to its parents. To me it is quite obvious that children to not have the maturity to understand sin and its consequences. At what age do we become "accountable?" I cannot give you an age, as the Bible does not do so, but your question is about unborn children. Surely they are innocent!! Jesus implied that children are innocent and that they will automatically be with God. Matthew 18:1-5 and Matthew 19:13-15 have Jesus telling the people that the secret of entering the Kingdom of Heaven is to become like a child. He does not actually say here that when infants die they are in heaven, as this was not the question in context, but surely it is implied indirectly by what Jesus said about children.
I am not in the place of Judge. No human being is. We ought to leave such judgment to God, but you can be assured that unborn infants and young children will not go to hell.
Where did this reprehensible idea that children might go to hell come from? Certainly not from anything Jesus said. The idea that babies might go to hell comes from a false doctrine which originated in the fourth of fifth century. It is most easily tied to the theology and teaching of the late fourth/early fifth century Christian teacher Augustine. By this time, it had become common practice in Christianity to baptize babies. Why, Augustine asked, are we doing this? What he should have said is that this is a very dangerous and unbiblical practice. Baptism only acts to bring salvation to those who have put their faith in Jesus and repented of their sins. Obviously babies cannot do this!!! Nevertheless, the fact is that baptizing babies very slowly crept into Church practice in the third and fourth centuries. Augustine concluded that children must be baptized because they are born guilty of the sin of Adam. They are born with what is sometimes called "Original Sin." The argument which Augustine used involves the idea of Predestination. This false doctrine is another matter which will take me too far from your original question. Suffice it to say that the idea of tiny babies going to hell because of a sin committed by Adam and Eve is is blatant conflict with the Bible on many levels. Let us reject this ungodly false teaching of Original Sin. Babies are innocent and will be with God.
John Oakes, PhD