- Identical twins have the same DNA sequence because they originate from a single fertilized egg.
- This means their blood group and eye color are typically identical. However, fingerprints differ due to unique environmental factors affecting skin development in the womb.
- These factors create distinct ridge patterns, making fingerprints a reliable identifier even in identical twins.

Reference: Ganong's Review of Medical Physiology, 26th Edition, Chapter 4, Page 48.