DNA profiling is one of the most reliable techniques we have, but it can be misused.
The UK is home to more than 3,600 apple varieties - but they can't be told apart by look or taste alone.
Our ability to reconstruct physical features from DNA is advancing, but can we ensure the privacy of "anonymised" genetic data if we can predict the face of its owner?
Facial recognition software isn't ready for face-in-a-crowd applications. Specialist police officers are far superior at spotting criminals.