Town of birth and birth certificates.
Sometimes you can reveal information that may seem of no help to a person seeking to get control of your life. An example: once I received a telephone call from an insurance agent (? )who quoted my birthdate month and year. He wanted the name of the town where I was born. I told him he had no need for that for insurance purposes and hung up. The risk: he writes to the county seat offices, quoting the birthdate information, and requests a birth certificate. He no doubt would have received it and away goes my identity.