Romans 2:11-16
11 For there is no partiality with God. 12 For all who have sinned without the Law will also perish without the Law; and all who have sinned under the Law will be judged by the Law; 13 for not the hearers of the Law are just before God, but the doers of the Law will be justified. 14 For when Gentiles who do not have the Law do instinctively the things of the Law, these, not having the Law, are a law to themselves, 15 in that they show the work of the Law written in their hearts, their conscience bearing witness, and their thoughts alternately accusing or else defending them, 16 on the day when, according to my gospel, God will judge the secrets of men through Christ Jesus. NAS
God is just and righteous and as we are told in the OT (where we learn about the nature of God):
Ezekiel 18:3-4
4 "Behold, all souls are Mine; the soul of the father as well as the soul of the son is Mine. The soul who sins will die NAS
Now define sin. Children are born with a sin nature but children are not born sinners since in order to sin one must make a rational decision to rebel against the will of God.
The Bible does not teach infant damnation.