Why do twins look alike? // Identical twins // Fraternal twins // Do fraternal twins look alike??

Whenever we see a pair of identical twins, we get confused as they look similar.
The twins look identical because they are formed from one fertilized egg splitting into two during pregnancy.
When they are born, they share the same DNA, that’s why they normally look alike.

Mostly twins are born with the same gender, but sometimes opposite gender is born.
These twins are called as fraternal twins.
Fraternal twins occur when the two separate eggs are fertilized during pregnancy.
When they are born, they don’t share the same DNA.
In general, they share only about half the same genes.
This is a reason why some of the twins don’t look more alike than regular brothers and sisters.
Even though, identical twins share the same DNA.
Sometimes, we may have noticed the differences between identical twins.
Especially, twins grow older.
This is due to that after an egg divides into two, cells inside continue to divide as a natural part development of a baby who contains trillions of cells.
Each time a cell divides, the DNA in it has to be copied.
Over the millions and millions of cell divisions, the DNA mutations occur.

As a result, identical twins don't share same DNA by the time they are born.

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