The following words of the Lord Jesus about "little children" prove that He did not believe that little children will populate hell:
"Then people brought little children to Jesus for him to place his hands on them and pray for them. But the disciples rebuked them. Jesus said, 'Let the little children come to me, and do not hinder them, for the kingdom of heaven belongs to such as these'" (Mt.19:13-14).
At another place we see the Lord Jesus speaking about children and here the same truth can be seen:
"At the same time came the disciples unto Jesus, saying, Who is the greatest in the kingdom of heaven? And Jesus called a little child unto him, and set him in the midst of them, And said, Verily I say unto you, Except ye be converted, and become as little children, ye shall not enter into the kingdom of heaven. Whosoever therefore shall humble himself as this little child, the same is greatest in the kingdom of heaven" (Mt.18:1-4).
We can also see that children are also described as being "an heritage of the Lord":
"Lo, children are an heritage of the LORD: and the fruit of the womb is his reward"
(Ps.127:3).