Dizygotic Twin vs. Fraternal Twin

Attribute	Dizygotic Twin	Fraternal Twin
Number of Eggs Fertilized	2	1
Genetic Similarity	50%	50%
Placenta	Can be separate or shared	Always separate
Gender	Can be same or different	Can be same or different

Definition

Dizygotic twins, also known as fraternal twins, are twins that develop from two separate eggs fertilized by two different sperm cells. Fraternal twins are no more genetically similar than any other siblings, sharing approximately 50% of their DNA. Fraternal twins can be of the same or different sexes. They are the most common type of twins, accounting for about two-thirds of all twin births.

Similarities

Despite the differences in how they are conceived, dizygotic twins and fraternal twins share many similarities. Both types of twins are born at the same time and are considered siblings. They may or may not look alike, just like any other siblings. Dizygotic twins and fraternal twins also have the same chances of inheriting certain genetic traits from their parents.

Genetic Makeup

One of the key differences between dizygotic twins and fraternal twins lies in their genetic makeup. Dizygotic twins, being the result of two separate fertilization events, are no more genetically similar than any other siblings. They share approximately 50% of their DNA, just like any other siblings born at different times. Fraternal twins, on the other hand, are genetically similar to any other siblings, sharing about 50% of their DNA.

Physical Characteristics

When it comes to physical characteristics, dizygotic twins and fraternal twins can vary greatly. Dizygotic twins may or may not look alike, depending on the genetic traits they inherit from their parents. Fraternal twins, like any other siblings, can also look similar or different from each other. The physical resemblance between dizygotic twins and fraternal twins is not determined by their twin status but rather by the genetic traits they inherit.

Gender

Another difference between dizygotic twins and fraternal twins is their gender. Dizygotic twins can be of the same or different sexes, as they are the result of two separate fertilization events. Fraternal twins, on the other hand, can only be of the same sex or different sexes if they are boy-girl twins. The gender of fraternal twins is determined by chance, just like any other siblings.

Chances of Conceiving

When it comes to the chances of conceiving dizygotic twins versus fraternal twins, there is a significant difference. Dizygotic twins are more common than fraternal twins, accounting for about two-thirds of all twin births. The chances of conceiving dizygotic twins are influenced by factors such as maternal age, family history of twins, and certain fertility treatments. Fraternal twins, on the other hand, are less common and occur randomly in about 1 in every 80 pregnancies.

Conclusion

In conclusion, while dizygotic twins and fraternal twins share many similarities, such as being born at the same time and being considered siblings, there are also key differences between the two types of twins. Dizygotic twins are the result of two separate fertilization events and share approximately 50% of their DNA, just like any other siblings. Fraternal twins, on the other hand, are genetically similar to any other siblings and share about 50% of their DNA. The physical characteristics and gender of dizygotic twins and fraternal twins can vary, depending on the genetic traits they inherit. Overall, understanding the differences between dizygotic twins and fraternal twins can help shed light on the fascinating world of multiple births.