Leah Sullivan, 4 years old, and Erin Sullivan live in the Scottish village of Inverness.
After their mother noticed a remarkable trait in the growth and behavior of the girls, the twins became famous.
This phenomenon, according to Zoya, 42, is “two sides of the same coin.” From the way they part their hair to how they use utensils, Leah and Erin do everything exactly opposite.
The twins sleep facing different directions in the same position. In photos, Leah is usually on the left, and Erin is on the right.
The girls seem to mirror each other while walking and interacting with each other.
The twins are radically different from each other by nature, as if they were destined to be a pair.
Experts refer to this phenomenon as “mirror twins.”
This term is used to describe twins with distinctive traits, such as birthmarks, dominant hands, or other opposite features that match as if they were looking in a mirror.
About 25% of all identical twin pairs experience this phenomenon.
It is not known what causes some siblings to mirror each other. It is believed to happen when the egg splits later in the fertilization process.
Between 4 and 8 days after conception, a fertilized egg divides into two embryos, producing identical twins.
Mirror twins are thought to result from the egg’s separation at a later time, between the ninth and twelfth days.
But this theory has not yet been scientifically proven.