Identical and fraternal twins fascinate many people. And they often wonder how they come to be. Both types of twins offer unique insights into human development and biology. And in this article, you’ll learn more about the differences and similarities of each set.
What are Identical twins and Fraternal twins?
You’ve heard the terms “identical twins” and “fraternal twins” before, but what do they mean?
Identical Twins
Most of us have seen identical twins and their physical similarities amaze us. But what exactly are they? Identical twins form when a single fertilised egg splits in two. It creates two separate embryos with the same genetic information.
Because they develop from the same egg, they share the same DNA and are always the same gender. Identical twins are also known as monozygotic twins. It’s interesting that identical twins don’t always look exactly alike.
They may have different hair or eye colors. Or that develop in a different manner due to their environment. Such as one twin is more exposed to more sunlight than the other. So while they may start out looking alike, identical twins often develop their unique features over time.
Image source: iStock
Fraternal Twins
Fraternal twins are two babies born at the same time. But they’re from two different eggs fertilized by two different sperm cells. Because they come from two separate eggs, they can be either the same sex or different sexes. Fraternal twins are also called “dizygotic twins.”
Some people think that fraternal twins look a lot alike. But they usually don’t look more alike than any other siblings who aren’t twins. One study found that, on average, fraternal twins share about 50 per cent of the same genes.
That means they’re no more alike than any other brother or sister. There’s something special about the bond between fraternal twins. Even though they are no more similar in genes than any other siblings.
Fraternal twins are also more common than you might think – about 1 in every 80 births results in twins! Fraternal twins are more likely to be born when the mother is older.
How to tell if twins are Identical or Fraternal from ultrasound?
Ultrasound is a medical procedure that uses sound waves to look at a baby inside the womb. This can help determine if the baby is healthy and what gender it is. It is also a standard for determining whether twins are identical or fraternal.
Here are three ways doctors can use ultrasound to determine the type of twins:
- The first method is looking at the placenta. A fraternal twin pregnancy will have two placentas while an identical pregnancy will have one.
- The second way doctors use ultrasound is by looking for a membrane separating them. Fraternal twins will usually have their amniotic sacs and chorions. If there are two separate sacs, the twins are fraternal; but, if there is only one, they might be identical.
- The third way to tell if twins are identical or not via ultrasound is by observing how many embryos there are. If there’s only one embryo, the twins are fraternal. But if there are two embryos with identical features, they might be identical.
These methods can help doctors predict if the twins are fraternal or identical. It’s not 100% accurate, and doctors may need further tests.
What are the similarities between Identical Twins and Fraternal Twins?
Identical
The similarities between identical twins are striking. They look alike, talk alike, and even think alike. But there are some differences between identical twins that you may not know about.
Identical twins have the same DNA. And they share many of the same physical characteristics. They can also have similar personalities, interests, and behaviours. Because they were raised in the same environment by their parents and other family members.
Fraternal
The similarities between two fraternal twins are pretty incredible.
They have the same genes but don’t share any of the same DNA. They have the same parents but don’t share a single umbilical cord. They might look exactly alike, but they’re not identical.
But even though they’re not identical, they share some remarkable similarities. For example:
- They probably have similar mannerisms and habits. It could be because raised in the same household by their parents
- They likely think about many of the same things. Because they often share the same interests or hobbies.
- They might both enjoy eating hotdogs with mustard. Because their mom bought them from the same grocery store on Sunday nights when she was home from work.
Image source: iStock
What are the differences between identical twins and fraternal twins?
Identical
Identical twins are often mistaken for the same person, but they have a lot of differences. Here are some of the most obvious ones:
- They’re not literally identical
The easiest way to tell them apart is by their appearance. Identical twins don’t look exactly alike. Because they’re not 100 per cent genetically identical. So it’s easy to spot physical differences between them.
- They have different fingerprints
Each twin has a unique set of fingerprints, like everyone else!
- They have different blood types
It is another way to tell them apart if you know your twins’ blood types (which you should). For example, if one twin has type-A blood and another has type B this can sometimes be enough to tell them apart without having to do anything else!
- They might have different birthmarks or scars
They could be from childhood injuries that heal differently or leave behind differences in pigmentation between the two skin cells in that area. For example, one twin might have a scar on her leg from falling off her bike as a kid.
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They could have different behaviors and personalities
They don’t always behave like—even if you’re trying to raise them the same way! Identical twins will often develop their unique personalities over time. It can be from their experiences growing up together and apart.
Fraternal
The idea of twins fascinates us. And we often wonder if they are identical. Fraternal twins are two different people who happen to be born in a simultaneous manner. Though they may look alike, there are many differences between fraternal twins.
For one thing, they have different DNA. They share a common placenta and are the same general size and shape, but they each have their own individual set of chromosomes. It means they are not genetically identical. They’re likely to have different physical characteristics.
- They can have different blood types
It is because genes determine blood type, and each twin gets a different set of genes from their mother. For example, if one twin has type A blood and the other has type B, they got different genes for blood type from their mother.
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More likely to be different genders
Fraternal twins are more likely to be of different genders than identical twins. Studies have shown that the gender ratio of fraternal twins is about 50/50. While the gender ratio of identical twins is more skewed towards having two of the same gender.
So why the difference? Experts believe it has to do with how the fertilized egg splits into two. With fraternal twins, the egg splits soon after fertilisation and each half develop into its embryo.
So if you’re expecting fraternal twins, there’s a good chance one will be a boy, and one will be a girl. But if you’re expecting identical twins, it’s likely they’ll have the same gender.
- They Can Have Different Personalities and Interests
When it comes to their personalities, fraternal twins are often quite different. One twin may be outgoing and social, while the other is shy and introverted. One may be creative and artsy, while the other is more logical and analytical.
The differences between fraternal twins can be quite striking. And they often help to balance each other out. As a result, these pairs often have a close bond that lasts a lifetime.
Image source: Stock
Republished with permission from theAsianparent Singapore
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