“I don’t give out that information (as a matter of principle/because my mother told me not to/because people close to me have been victims of identity theft/because I’m old enough to know better).” Or some variation thereof. It’s enough to say that you don’t because you choose not to, but some people will belabor the point until you give an answer that has the ring of finality and can communicate that it isn't a matter of debate, but a matter of conscience, or rationale, or whatever principle(s) guide you.
Or you could provide a joke answer that is absurdly high or low or wrong, like saying that you weren’t born yesterday, or that you were born at night, but not last night, or in the day, but not yesterday. This might work for those who you are closer with personally, but some may find this kind of answer dismissive and will persist or get upset. If in doubt, use the principle-based approach I mentioned above instead or in addition to the joke one, as a way of showing that you’re answering in good faith and take their question seriously as asked.
“I don’t give out that information (as a matter of principle/because my mother told me not to/because people close to me have been victims of identity theft/because I’m old enough to know better).” Or some variation thereof. It’s enough to say that you don’t because you choose not to, but some people will belabor the point until you give an answer that has the ring of finality and can communicate that it isn't a matter of debate, but a matter of conscience, or rationale, or whatever principle(s) guide you.
Or you could provide a joke answer that is absurdly high or low or wrong, like saying that you weren’t born yesterday, or that you were born at night, but not last night, or in the day, but not yesterday. This might work for those who you are closer with personally, but some may find this kind of answer dismissive and will persist or get upset. If in doubt, use the principle-based approach I mentioned above instead or in addition to the joke one, as a way of showing that you’re answering in good faith and take their question seriously as asked.