will someone go to hell if they were never tought christianity?

Tough question, huh?
Many people struggle with this one.
Fortunately, truth has been restored on earth. Many religions will claim that if a person who has never had the opportunity to hear about Jesus or his gospel will got to hell. That does not sound like a just God, does it?
It is true that
"He that believeth and is baptized shall be saved; but he that believeth not shall be damned.” –Mark 16:16
Also, “Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God.” –John 3:5

Just as you asked, what DOES become of those who have never heard the gospel and hence, never had an opportunity to accept or reject it?

Simply put, everyone will have an opportunity to hear the gospel and choose for themselves, whether or not to believe it. Thus, everyone will be judged fairly. Paul said “For as many as have sinned without law shall also perish without law: and as many as have sinned in the law shall be judged by the law….” –Romans 2:12
Now, this does not mean that someone who has not had the gospel will not be accountable for anything they have done, it just means that provisions are made.
I’m about to reference a lot of scriptures, so please be patient with me and follow along.
After the death of Christ, he went and visited the spirits of those who had already died, but had not been resurrected yet.
“For Christ also hath once suffered for sins, the just for the unjust, that he might bring us to God, being put to death in the flesh, but quickened by the Spirit:
‘By which also he went and preached unto the spirits in prison.” -1 Peter 3:18-19
“For for this cause was the gospel preached also to them that are dead, that they might be judged according to men in the flesh, but live according to God in the spirit.” -1 Peter 4:6 (dead in this verse comes from the Greek Nekros, which means corpse, or dead-it does not mean alive and spiritually dead).
Christ essentially opened up missionary work to those who had not had an opportunity to hear the gospel yet.
So, when did Jesus have an opportunity to go preach to these spirits? Well, when he was dead is the answer. We know that Christ’s body was in the tomb for 3 days, but where was his spirit? He was not in heaven for those whole three days. After Christ’s resurrection, Mary ran up to him and was going to touch the savior, but he said, “Touch me not; for I am NOT YET ascended to my Father.” –John 20:17
This doctrine is not discussed much these days, simply because most churches and or believers don’t understand or believe it. It was a common belief amongst Christians. If you look at history, you can even find paintings depicting Christ opening the gates of those kept in captivity who had not heard the gospel (example above-this is a catholic depiction of Limbo, but it's close enough to suit this entry's purpose).

In conclusion, every person will be accountable for their actions, and all will have the opportunity to accept or reject the gospel, and thus all will be judged fairly. It’s a beautiful doctrine and shows how just and loving our Heavenly Father is.

Best Wishes,
Rusty