A view that hasn't been addressed by any answer so far:
There are in a sense two aspects to the scenario; firstly, that the person in question was born when and where they were, and secondly that the Gospel has not reached that time and place.
As to the first, the person's lack of control over the circumstances of their birth. It may be unfair, but not on the part of God, because while it is not the person's fault that they are born in the time/place/circumstances they are, nor is it God's. Rather, it is the result of a long chain of what were ultimately human decisions, from that person's ancestors' decision to settle in that location, to their parents' decision to procreate. Did God know this would happen? Absolutely. Was it part of his plan? Absolutely. But was it also ultimately the result of human decision and action rather than God's? Also absolutely.
As to the second, the absence of the Gospel when/where they were raised, this is again ultimately the result of human decisions/actions. In this instance, it is the failure of Christians to reach these people, as well as the decisions of those people and their ancestors that resulted in their hard-to-reach location. The bible makes it clear in several places that it is our responsibility as Christians to spread the Gospel to those who have not heard it. For example in Romans 10:14-15a,
"How then will they call on him in whom they have not believed? Ans how are they to believe in him of whom they have never heard? And how are they to hear without someone preaching? And how are they to preach unless they are sent?". Thus, the absence of the Gospel in any area is not God's failure, but ours, which I think gives more weight to the duty of evangelism and mission work than many believe.
Personally, I do not believe that it is possible for the unreached to be saved without explicit knowledge of the Gospel, for scriptural reasons and the fact that people are not raised in a vacuum with nature; the combination of our corrupt natures and traditions that are inevitably passed down in any culture, I believe, prevent anyone from being saved even if the general revelation of nature were sufficient.
One aspect of the question I did not explicitly lay out was whether God giving said person life, knowing their fate, is cruel or unfair, as opposed to the child being stillborn or a 'philosophical zombie'. I'm inclined to think that, as an extension of giving humanity free will, He has allowed us autonomy to have children when/where we will. Just as free will results in sin yet is still permitted, so does deciding when to have children result in children born who will never be saved. The argument for this being unfair seems to rest on the unreached nature of the circumstances they are born into, which I believe I have demonstrated is the result of man's actions, not God's. I do not believe we are in a position to say whether it would have been better for creation as a whole if God had prevented that child from being born.