Difference Between Identical and Fraternal Twins

What Are Identical Twins?

Identical twins, referred to as monozygotic twins, are siblings, and they are delivered from a single fertilized egg that partitions into two embryos during early development. This means that they consist of the same genetic material and are essentially genetically identical, with very slight differences. The same gender is always shared by identical twins and has similar physical appearances, although they might differ in personality, interests, and other non-genetic factors. Identical twins are not more common than fraternal twins, which are conceived from two different eggs fertilized by two different sperm.

What Are Fraternal Twins?

Fraternal twins, also called dizygotic twins, are siblings who are born at the same time but have developed from two separate fertilized eggs. They are genetically no more similar to any other pair of siblings, as they share around fifty percent of their genetic material, just like any two siblings born from different pregnancies.

Fraternal twins might be of the same or opposite sex and look very similar or completely different. The likelihood of having fraternal twins is influenced by several factors, including family history, maternal age, and fertility treatments. Unlike identical twins, who reproduce from a single fertilized egg, fraternal twins are no more likely to share physical or behavioral traits than they usually share.

What Is the Difference Between Identical and Fraternal Twins?

Another name for identical twins is monozygotic twins, developed when a single fertilized egg divides into two embryos. Due to this, identical twins share the same DNA, and as such, they often share many physical and behavioral traits.

The following are the differences between the identical and fraternal twins:

• Same Physical Appearance: Identical twins often look almost similar, with the exact eye color, hair color, facial features, and body type.

• Same Blood Type: Identical twins have the same blood type, as they share the same genetic material.

• Similar Personality Traits: Identical twins often have similar personality traits, like being outgoing or introverted, confident or shy, and other examples.

• Similar Intelligence: Identical twins tend to have similar levels of intelligence, as intelligence is primarily determined by genetics.

• Same Fingerprints: Although identical twins share the same DNA, they do not have the same fingerprints. Even though their fingerprints are often very similar and may be difficult to distinguish.

• Higher Likelihood of Developing the Same Medical Conditions: Identical twins have a higher likelihood of developing the same medical conditions, such as diabetes, heart disease, and certain types of cancer, as their genetics are identical.

Fraternal twins, also referred to as dizygotic twins, are twins that are developed when two separate sperm cells fertilize two separate eggs. As a result, fraternal twins have distinct genetic profiles and may have different physical features, personalities, and characteristics.

The twin's common features are as follows:

Fraternal twins might be exact or distinct in gender.

• They may or may not look alike, as they have separate genetic profiles and can inherit different physical traits from their parents.

• They may have different blood types, hair colors, eye colors, and other physical characteristics.

• There is no distinction between identical siblings and fraternal twins, although they may share some similarities due to growing up in the same environment.

• Fraternal twins may have a higher likelihood of developing certain medical conditions, such as twin-to-twin transfusion syndrome or preterm labor, compared to singleton pregnancies.

• Identical twins are less prevalent than fraternal twins, accounting for approximately two-thirds of all twin pregnancies.

• The chances of having fraternal twins can be influenced by factors such as maternal age, family history, and fertility treatments.

What Are the Factors Which Increase the Chances of Having Twins?

The following are the factors that elevate the chances of having twins:

• Age: As women age around thirty-five years, they expel more eggs in number in ovulation, which can increase the chances of having fraternal twins.

• Family History: Having a family history of twins on the mother's side can increase the chances of having twins. This is because the tendency to release multiple eggs can be passed down through generations. This is a hereditary factor.

• Fertility Treatments: Women who undergo fertility treatments such as in vitro fertilization (IVF) are more likely to have twins or high number multiples, as multiple embryos may be implanted to increase the chances of a successful pregnancy.

• Ethnicity: African American women are more likely to have twins than other ethnic groups, while Asian women are less likely.

• Nutritional Status: Women who are overweight or obese have a higher chance of having twins. It occurs due to the elevated expulsion of certain hormones that can stimulate the release of multiple eggs.

The identical twins' occurrence is very random and not affected by the causative factors.

What Are the Health Risks of Having Identical and Fraternal Twins?

Identical Twins:

Considering that they have matching DNA, identical twins have the same gender. The following are the health risks of having identical twins:

• Prematurity: Identical twins are often born premature, leading to respiratory distress syndrome, jaundice, and other complications.

• Birth Defects: Identical twins may have higher complications like birth defects, congenital cardiac disease, or neural tube defects.

• Twin-to-Twin Transfusion Syndrome: In some cases, identical twins may develop twin-to-twin transfusion syndrome, which occurs when there is elevated blood flow to one of the twins. This can lead to complications for both twins.

• Growth Issues: Identical twins may have growth issues, including being smaller than average, due to their shared placenta.

• Mental Health Issues: Identical twins may elevate complications of health disorders like anxiety, depression, and schizophrenia.

Fraternal Twins:

Fraternal twins have elevated health issues than singletons, but they may have a higher risk of certain conditions due to their shared environment in the womb. These conditions include.

• Prematurity: Fraternal twins may be born premature, leading to respiratory distress syndrome, jaundice, and other complications.

• Birth Defects: Fraternal twins may have higher complications like cleft lip and palate.

• Twin-to-Twin Transfusion Syndrome: Fraternal twins may also develop twin-to-twin transfusion syndrome, although it is less common than in identical twins.

• Gestational Diabetes: Women carrying fraternal twins may have a higher risk of gestational diabetes, which lead to hazards for the mother and babies.

• Preeclampsia: Women carrying fraternal twins may also have a higher risk of preeclampsia, an adverse medical condition that can lead to elevated blood pressure and damage to organs.

Conclusion:

Having twins, whether they are identical or fraternal, comes with certain health risks. Expectant parents must receive prenatal care properly and monitor their babies closely throughout pregnancy to minimize these risks and guarantee an ideal result for the mother and babies. Because they usually share a placenta, identical twins can frequently be distinguished while still in the womb. Fraternal twins can be determined after delivery if they have distinct blood types or are of different genders (a boy and a girl). However, genetic testing (a twin zygosity DNA test) is the only way to conclusively determine that they are identical twins.