I wonder if the right maths applied to existing genetic and forensics big data sets could produce the 33 questions.

I'd imagine that genetic markers would be the best way to do to (Disclaimer: I'm no biologist and might have made completely wrong assumptions here). They're less likely to change than, say, someone's political or religious beliefs; one could get a nasty hit on their head and forget.

The thing with genetics is that they can change over time. Some gene's turn on and off. Attributes like your face and fingerprints change over time. They're not constants.

If you could identify a set of 33 lifetime constants, you'd end up with a life-long UUID. If you expanded beyond 33 bits and included genetic markers which change over time, such as gene's which flip on/off, you could end up with a point-in-time (PIT) UUID.

    UUID     = Constant throughout life.
    PIT+UUID = UUID plus markers identifying you at a particular point in time.

A constant would be something like, do you have a Y chromosome? (there is fault in this question: XYY syndrome)

Also, you'd probably need more than 33 bits. 33 will encompass all living humans today in 2013 ADE, but would have to be expanded as the living population grows, and to include the billions of deceased humans.

In the end, a "true" unique identifier, encompassing any human, would be their UUID plus a list of all PIT+UUID's they generated during their lifetime. Or in english, an entire record of their genetics from start to end:

    struct LIFETIME_UUID {
        void * uuid;
        void * pit_uuid_TIMESTAMP1; 
        void * pit_uuid_TIMESTAMP2; 
        void * pit_uuid_TIMESTAMP3;
        ...
    };

That should eliminate conflicts in edge cases like identical twins or cloning.

DNA is your UUID/GUID

Presuming you're not a chimera http://en.wikipedia.org/wiki/Chimera_(genetics)

Unless you're one of a set of twins/triplets/etc.

append datetime string of birth. Boom problem solved.

What if the twins are delivered via Caesarean, with the exact same datetime recorded? Including datetime (even as a string) also includes the aforementioned falsehoods about time.

unless you have a twin, or other tuplet siblings.

or a clone:)

Unless you're a twin