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Argentina — Citizenship by Descent
Likely
This is the strongest form an Argentine claim takes.
A child of a parent born in Argentina can take Argentine nationality by opcion - an option you exercise rather than a naturalisation you apply for. There is no residency requirement, no language test and no age limit. Adults can do it, and it stays open after the Argentine parent has died.
What it turns on is documents rather than facts. You will need your parent's Argentine birth certificate and their DNI, your own birth certificate legalised or apostilled, and a current identity document of your own. Filiation is proved to an Argentine federal judge, so the paperwork has to be exact and correctly legalised.
Where it happens depends on where you live: an Argentine consulate if you are abroad, RENAPER or a civil registry if you are in Argentina. Expect collecting the documents to take longer than the decision.
Tell us which country you are in, and whether you already have your parent's Argentine birth certificate, and we will tell you what is missing.