Birth records are public as they are a part of history. Over the last couple hundred years the keeping of birth records has been much more accurate so that you can find the birth certificates of just about everyone you know and more! Today finding these records is easier than ever before. In fact, you don't even have to leave your home to get the records of anyone's birth, you can do it all from the comfort of your own home.
How does this work? Like anything else, you can find things with the internet. You can go through birth records websites that will charge you a fee to get a hold of the record of your choice. Basically, this is a middle man that will search through the records of every state, city, and county to find the record that you are looking for. These can be especially helpful if you aren't sure of a specific city or county in a state but know that the birth took place in a specific state.