The numbers are no longer issued by area, to help prevent identity theft.

Also, you can change your SSN only in these circumstances:

• Your number is so similar to that of someone else in your family that it’s causing problems
• Your SSN was mistakenly issued to more than one person
• Someone stole your identity
• Using your current number exposes you to danger (domestic violence, harassment, etc.)
• You have a religious or cultural objection to some of the digits in your number (written documentation is required to validate this)

Not all children were issued SSN at birth, even now. I've had two relatives who had to work through affidavits to get their SSN issued or changed or otherwise corrected/combined.