Allah does not punish unless He sends a Messenger:

A clarification

On the basis of this verse, some leading Muslim jurists rule that people to whom the call of any prophet or messenger did not reach will not be subject to any punishment, despite their disbelief. There are other leading jurists who hold that those who deny the Islamic beliefs that can be understood through reason - such as, the existence of God and His Oneness etc. - will be punished for their disbelief, even if no call from any prophet or messenger has reached them. Of course, there will be no punishment for usual acts of disobedience and sins without prior call and transmission of the divine message by prophets. And there are still others who interpret 'rasul' at this place (15) in a general sense, whether he is a messenger or prophet, or whether it is the human reason itself - for, that too, in a way, is a messenger of Allah after all.

There will be no punishment for the children of Mushriks

Commenting on the verse: لَا تَزِرُ‌ وَازِرَ‌ةٌ (And no bearer of burden shall bear the burden of another - 15), it has been said in Tafsir Mazhari that this verse proves that the children of Mushriks and disbelievers who die before reaching adulthood will not be punished. The reason is that they will not deserve to be punished on account of the denial and disbelief of their parents. Sayings of leading jurists differ about this issue; its de-tails are unnecessary here.