What is the Difference Between Twins and Identical Twins?

The main difference between twins and identical twins lies in their genetic makeup and how they are formed:

1. Identical twins (monozygotic): These twins form when one fertilized egg (ovum) splits and develops into two babies with exactly the same genetic information. They share the same DNA and are genetically identical. Identical twins can be either male or female, as they have the same DNA.
2. Fraternal twins (dizygotic): These twins form when two eggs (ova) are fertilized by two sperm, producing two genetically unique children. Fraternal twins share around half of their genetic information, just like any other siblings born at different times. They can be a mix of male and female, as they have different DNA.

Some key points about twins and identical twins include:

• Identical twins may or may not share the same amniotic sac, depending on how early the single fertilized egg divides into two.
• Fraternal twins usually develop separate amniotic sacs, placentas, and supporting structures.
• Identical twins have the same DNA, but they may not look exactly identical due to environmental factors.
• All twins, whether fraternal or identical, are truly separate and unique individuals.

To determine if twins are identical or fraternal, a DNA test can be conducted using a sample of cheek cells or blood group examinations.

Comparative Table: Twins vs Identical Twins

Here is a table comparing the differences between twins and identical twins:

Fraternal twins, also known as dizygotic twins, form from two different eggs fertilized by two different sperm cells, resulting in genetic code similar to that of any other siblings. They usually have different genders and may look different from each other. The formation rate of fraternal twins varies by geography and ranges from 6 to over 20 per 1,000 births.

Identical twins, also known as monozygotic twins, form from the splitting of the same fertilized egg, resulting in nearly identical genetic code. They almost always have the same gender and share many of the same physical characteristics. The likelihood of identical twins is the same around the world, occurring in about 3 in 1,000 births.