Do identical twins communicate telepathically?
- Minhoo Jeong
- Apr 16
- 2 min read
April 16 2025
By Minhoo Jeong
'Twins' are mysterious and fascinating because they don't meet very often. How did an identical or similar creature come to be in my mother's womb with me? From ancient mythology to modern scientific research, twins provide valuable insights into genetics, psychology, sociology, and many other fields. In particular, the differences and similarities between identical and fraternal twins provide important evidence for the “nature vs. nurture” debate. As living proof of the complex relationship between genetic and environmental influences, twins are more than just curiosities; they inform us about the nature of human identity and how we are connected to each other. Their similarities and differences provide insight into how genetics and environment interact and influence us.
The scientific categorization of twins is based on the way they are formed. Identical twins are created when a single fertilized egg splits into two during early development, while fraternal twins are created when two different eggs are fertilized by different sperm. This fundamental difference sets the stage for explaining the genetic, physical, and psychological similarities and differences between identical and fraternal twins. While identical twins share 100% of the same genes, fraternal twins share about 50% of their genes, just like regular siblings. Because of this, identical twins have the same sex and are very similar in appearance, body structure, and attitudes toward things and life, whereas fraternal twins' sex is literally random; their appearance can be very different and often has the same degree of similarity that siblings share.
There are some interesting exceptions and phenomena that go beyond this simple categorization. First, there are “semi-identical” or “sesquizygotic” twins, twins who are only partially identical because one egg was fertilized by two sperm. In a case published in 2019 by researchers at the University of Queensland in Australia, sesquizygotic twins were found to share 100% of their mother's genetic information, but only part of their father's genetic information. A second interesting anomaly is the “chimera” twin. This is when two fertilized eggs fuse during early development and become one individual. The resulting individual may have two different sets of DNA. Some chimeric twins have physical characteristics such as heterochromia, where the irises of the eyes are different colors.
