The question of whether or not babies go to heaven when they die is an issue long debated by Christians.

For years, believers have been arguing about the so-called age of accountability, or the age when a child becomes accountable for his or her wrongdoing. This idea hangs on the principle that because very young children have a limited capacity to understand, they are not held accountable for sin until they reach the age when they have enough understanding.

However, the Bible does not explicitly say anything about the age of accountability. So what happens to babies when they die, do they go to heaven or do they go straight to hell?

Christian author and founder of DesiringGod.org John Piper believes infants who die go to heaven.

Piper clarified this does not mean he believes babies are not affected by the fall of man or the original sin. On the other hand, he said infants are "participants in the Fall" and "participants in the original sin."

Piper said the more important question is whether God can cover the babies' sin before they are able to believe and make decisions. He believes God can.

"The question is whether God has a way to cover their sin even before they have a chance to believe," Piper said. "Babies are not mentally able to put faith in Jesus yet, at least not in any terms that we ordinarily understand. And so I think that God provides another way to cover their sin."

He cited Romans 1:19-20 as the basis for his answer.

The verses say, "For what can be known about God is plain to them, because God has shown it to them. For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse."

Piper said the biblical passage means mankind would appear to have an excuse to not know God if they have not witnessed the invisible attributes of God in the beauty of creation.

"And so, because I don't think little babies can process nature and make conclusions about God's grace, glory or justice, it seems they would fall into the category of still having an excuse," he explained.

He believes that at the judgment day, children who died as babies "will be covered by the blood of Jesus," and that God allows it to be so "for His own wise purposes."

Piper also believes these children will "come to faith, either in heaven immediately or later in the resurrection."

"And God will not condemn them because he wants to manifest openly and publicly that he does not condemn those who did not have the mental capacities to put their faith in him," he said.

"Therefore I hold out hope to parents that the loss of an infant is not their eternal loss."