Do you believe a baby is born guilty, in sin?
If so, then I hope you also believe in infant baptism.
Yes, I believe that all babies are descendants of Adam and have inherited his sin nature. I don't believe in infant baptism, as I believe it is a statement of one's belief that their sin nature is dead and buried, and that they are a new creation in Christ.
Romans 3:10-18...
“There is no one who is righteous, not even one;
there is no one who has understanding;
there is no one who seeks God.
All have turned aside; together they have become worthless;
there is no one who shows kindness;
there is not even one.”
“Their throats are opened graves;
they use their tongues to deceive.”
“The venom of vipers is under their lips.”
“Their mouths are full of cursing and bitterness.”
“Their feet are swift to shed blood;
ruin and misery are in their paths,
and the way of peace they have not known.”
“There is no fear of God before their eyes.”
Romans 6:4, "Therefore we were
buried with him by baptism into death, so that, just as Christ was raised from the dead by the glory of the Father, so we also might walk in newness of life.
I do not believe that God holds the sin nature of an infant against him/her. He is a forgiving God and would never do that. Once a child becomes conscious of sin and continues to sin regardless, s/he is then responsible for their behavior. Bar/bat mitzvah occurs at age 13 in Judaism. Christian confirmation generally occurs at the same age, so my best guess is that 13 is the age at which one is held accountable for their actions.