Actually Shaun, due to the way the gospel has spread as the world's population has increased, the percentage of people who have ever lived who have not heard some form of the gospel is small (and the longer the Lord tarries, the lower that percentage will be). Nevertheless, I understand your concern for those who simply never had a chance to hear it. I think deep down inside we know that if they were condemned simply for being "unlucky" by being born at the wrong time or place, that would seem unfair. But does God actually require us to have heard the gospel to get into heaven? Not in every case. To be sure, if you've heard it and rejected it, you can count on being excluded, but the Bible has numerous references to folks who never heard of Jesus that we can be sure are in heaven, such as Melchizedek. Peter says in Acts 10:34-35 that "God  does not show favoritism, but accepts men from every nation who fear Him and do what is right."

There seems to be a correlation between those who "fear Him and do what's right" and those who accept Christ if they're given a fair chance. Basically, these seem to me to be the same types of people, just with different levels of revelation. Revelations 5:9 says that Christ purchased many from "every tribe and language and people and nation." Since we know that some of these groups ceased to exist without ever hearing of Christ, this also seems to indicate that some will get to heaven without exposure to the gospel.

What about infants and those who die in childhood who have not really had revelations to respond to? Matthew 11:20-24 gives the principle that those who would have responded to greater revelation will receive credit for that in their judgment. This is a key principle, in my opinion. It solves so many soteriological riddles. If the Lord is judging us all this way, it's all fair no matter what type of life one has. It's very simple; if you would have accepted Christ given a fair chance, that "WOULD HAVE" will be credited to you in judgment, and you'll be fine. God in his infinite wisdom knows all possibilities, actualized or not, so He knows what every creature would do under any possible hypothetical circumstance, and all "subjunctive counterfactuals of creaturely freedom". Therefore He knows whether or not any being would accept Him given a fair chance.

Many believe in an "age of accountability" theory where infants and others who perish before a certain age go directly to heaven without exception. Dr. Craig takes this view, but I respectfully disagree with him. How could a child who would turn into a "Hitler" or a "Stalin" if he had stayed alive, be allowed into heaven? I just can't believe God would give free access to ALL who are cut short without regard to their nature. If their nature is such that they would have eventually accepted the gospel given a fair chance, then absolutely. If not, why let 'em in?

In the FAQ section of the website, check out "Questions on Middle Knowledge". Dr. Craig states that he doesn't believe God should judge people on what they "WOULD DO", but rather only what they've actually done. I love Dr. Craig and have been very inspired by his work, but I think he needs to adjust his view here, as he himself has written within several pieces about the possibility that God has placed us in specific times/places based on exactly that--whether or not we would accept the gospel given the chance. If it's OK for God to have placed us in circumstances where we would not be exposed to the gospel, based on His knowledge of whether or not we would accept it given a fair chance, I don't see what would be wrong with Him simply judging all who never were exposed to the gospel on that basis. If anyone sees a flaw in my reasoning, I’d be happy to hear it.

His best to you.