I tried to baptize my baby at a local Catholic Church in Toronto, but the priest told me I need to provide documents proving I was baptized. I don't have such documents because I was baptized and confirmed in another country, and I don't even remember in which church. Without the paperwork from my country of birth the priest refuses to baptize my son. Is this really a requirement in the catholic church? Or is it possible to find another priest who is more easy going?
In order for a child to be baptized, there must be "a founded hope that the infant will be brought up in the Catholic religion" (Code of Canon Law, Canon 868 section 1). That is, the priest must judge it reasonable to believe that you will raise your child Catholic. This is reasonable from the church's point of view since it baptizes infants so that, growing in grace in the Church, they will be saved.
Is it necessary for you, then, to prove that you are baptized? Canon law has no such requirement. In fact, it's perfectly possible for the child of a non-Catholic to be baptized. (The complete requirements for valid, licit baptism of an infant are listed in Canon 868 of the Code of Canon Law). What's important is for the priest to feel comfortable with the idea that you'll raise your child Catholic. This is usually not a problem, especially if you have been a member of your parish for some time.
Did you explain this to the priest? Are you a regular parishioner at the church you intend to baptize your son? Is there a witness/sponsor of your baptism the priest could contact?
Essentially, you must somehow prove to the priest who will baptize your son that this is true:
Can. 868 §1 2/ there must be a founded hope that the infant will be brought up in the Catholic religion; if such hope is altogether lacking, the baptism is to be delayed according to the prescripts of particular law after the parents have been advised about the reason.
The lack of your baptismal certificate does not of itself impede the baptism of your son.
(A related story: My wife had a lot of trouble obtaining her baptism and confirmation certificate before our marriage. After both she and I called numerous times the out-of-state church holding the records, and even had a relative who lived nearby the church go there in person, they eventually sent copies of the certificate, but they said she was confirmed in the future, after year 2100! Nevertheless, it was sufficient proof for the priest that she is a confirmed Catholic and that we could both be married in the Church.)