What are Fraternal Twins

Twins, in simplest terms, are defined as two offspring born during the same pregnancy. Twins can be identical, i.e. with similar physical appearance or non-identical or fraternal, i.e., with dissimilar physical appearance. Here we will see more on fraternal twins, and the difference between fraternal and identical twins.

An Overview on Fraternal Twins

Also known as dizygotic twins or non-identical twins, fraternal twins are twins that are born when two eggs are fertilized individually by two sperm cells. The two fertilized eggs form two different zygotes which leads to the development of two non-identical twins. Two different placenta are formed which are sometimes even found to fuse into one single one. As they are formed due to two different fertilization methods, there are rare chances of the twins having similar genetic or chromosomal structure. You may find some similarities between two fraternal twins, but, these are merely because the two are of the same age and born to same parents. In most of the cases, fraternal twins are starkly different from one other.

For better understanding, we can compare the development of fraternal twins with the identical ones. In case of identical or monozygotic twins, only one single egg is fertilized by two different sperms which later is divided after fertilization. This is the major difference between identical and fraternal twins. Therefore, identical twins have a same genetic or chromosomal structure and they look identical. It should be noted that identical twins, in most of the cases, are found in offspring of same sex (twin boys or twin girls); whereas fraternal twins can be found in offspring of same or different sex.

Facts About Fraternal Twins

• They are more common than identical twins.
• Highest incidences are found in Africa with as many as 1 among 20 cases (In other parts of the world, 1 in more than 100 cases are found).
• Female fraternal twins have higher chances of giving birth to twins.
• They have different blood types.
• If a woman has fraternal twins during the first pregnancy, there are higher chances of having fraternal twins in the next pregnancy.
• Similarly, if a woman has fraternal twins as siblings, or in the maternal genetic line; she has more chances of giving birth to twins herself.
• On the other hand, there are several factors that increase a woman's chances of conceiving fraternal twins. Firstly, older woman (above 35 years of age), give birth to twins more commonly than younger woman. Secondly, use of birth control pills also leads to conceiving of fraternal twins.

Famous Fraternal Twins

• Alanis Morissette and Wade Morissette
• Ashton Kutcher and Michael Kutcher
• Aaron Carter and Angel Carter
• Billy Dee Williams and Loretta Williams
• Gisele Bundchen and Patricia Bundchen
• Jenna Bush and Barbara Bush
• Mario Andretti and Aldo Andretti
• Mark Waugh and Steve Waugh
• Mark Vincent and Paul Vincent
• Scarlett Johansson and Hunter Johansson

Lastly, one of the interesting facts is that twins have a unique emotional bond that is found for a lifetime. Ciao!