In "Doctrinal Discussion" Jason Lindahl writes:

Since the Bible says that we are judged based on the light we have, are the heathen better off being left alone so that they have an excuse for not living righteously? After all, they can't be held responsible for light they don't have, right?
There are at least three biblical reasons why this line of reasoning is faulty. First, Romans 1:19, 20 says, “Because that which may be known of God is manifest in them; for God hath showed it unto them" … These verses teach us there is at least enough biblical evidence in the physical universe to reveal the existence of an all-powerful Creator that is greater than any idol someone could construct…
Second, Romans 2 says that every person has a God-given conscience which leads him instinctively to view certain behaviors as wrong and others as right…
Third, Jesus told us in John 16:8 that the Holy Spirit is active in this world, and that part of His job is to convict every individual in it of sin, righteousness, and judgment …

See your Adult Insights for the full discussion of this thorny question!
Source: Building Christian Relationships: Adult Teacher's Insights, page 20.