A birth certificate is one of the most important documents a person must keep a copy of. Almost all major and official transactions - application for visas, passports, drivers license, opening a bank account, among others, require birth certificates to authenticate a persons identity. One has to present a birth certificate to acquire marriage license or get into college, even.
Hospitals have forms that have to be filled out with the assistance of the parents upon the birth of their child. It will contain details like the names of the baby and the parents, complete present address of the family, name of the hospital, and the babys biological information - birth weight, height and gender, as well as the exact date and time of delivery. The attending physician will authenticate the information. The parents will have to submit a copy to the city halls registry where a birth certificate will be prepared. An authenticated copy of the original is given to the parents, and the city hall keeps the original document.
Some transactions like applications for credit cards may not require an authenticated copy of your birth certificate - a photocopy of the authenticated copy may suffice. Sometimes, institutions may only require seeing your passport or drivers license - and you wouldnt get those without a birth certificate.
To avoid unnecessary trouble and inconveniences, always have an authenticated copy of your birth certificate at the ready. You wouldnt know when you need to submit one. Also, keep it in a secure place. You wouldnt want it landing in the hands of people with malicious intent who could steal your identity.
If you have lost your copy, you may obtain another from the city hall where you were registered. Remember that you can only get an authentic copy from the city hall. Forging your birth certificate is a criminal offense, because it is, after all, an official government document honored in major transactions.