Mirror Twins: Not as Rare as You May Think – The Full Guide

There are different types of twins, and each type is defined by certain factors. You have probably heard of fraternal and identical twins, but there are subtypes within each type.

Mirror twins are a type of identical twin, and they have unique characteristics.

What is a mirror twin? Mirror twins are defined as identical twins with reverse asymmetric features. If one twin has a freckle on the right cheek, the other might have the same freckle on the left cheek, though not every physical feature of mirror twins will be reversed.

Mirror twins are not a separate type of twin. They are simply a subtype of identical twins.

Mirror twins are created in the same way as identical twins but on a slightly different time table.

This small difference can alter the external characteristics of mirror image twins. In rare cases, it can affect even more than just their physical features.

Mirror Twins Definition

Mirror twins are identical twins with features that mirror each other. These twins can stand face-to-face, and it will look like they are staring into a mirror if you line up some of their physical features. 

One may be right-handed while the other is left-handed. They may have identical birthmarks on opposite arms in the exact same place. However, not all of their external physical features will mirror.

In very rare cases, some mirror twins will actually have internal organs that mirror, such as one twin having a liver on the right side and the other having one on the left. 

How Do Mirror Twins Happen?

Though not conclusive, it’s believed that mirror twins occur when the fertilized egg splits later in the process than usual. If the egg splits more than a week after conception, mirror twins are possible.

The creation of most identical twins occurs when the egg splits during the first week. This can result in mo mo twins or mo di twins, the two main types of identical twins.

If the egg waits to split until the seventh day or beyond, mirror twins are possible.

What’s the Difference Between Identical Twins and Mirror Image Twins?

Mirror twins are also identical twins, so the differences are subtle. With mirror twins, the fertilized egg splits later than usual, and that’s what creates the differences that set them apart from other identical twins.

Most identical twins will have features on the same side of the body, but mirror image twins have identifying features on the opposite sides.

Are All Identical Twins Mirror Twins?

No, only 25 percent of identical twins are mirror twins. Most identical twins are non-mirror twins.

Are Mirror Twins Considered Identical?

Yes, all mirror twins are considered identical. They come from the same fertilized egg that simply split later in the process than most. 

How Do You Know if You Are a Mirror Twin?

There is no test to find out if you are a mirror twin. While DNA can be tested to determine if twins are identical, mirror twins identify themselves when they notice they have mirrored features.

Their parents may also identify them as mirror twins when they notice the reverse asymmetric features in their children.

In rare cases, anomalies could alert doctors to check for the possibility of mirror twins. The presence of extra toes or a thumb that won’t bend could lead your doctor to look for signs of mirror twinning.

How Are Mirror Twins Diagnosed?

When twins notice they have physical features on different sides of their bodies that mirror each other, they may identify as mirror twins. 

In extremely rare cases, an X-ray can pick up situs inversus, a condition where the organs of one twin are on the opposite side of the body from where they should be.

However, most mirror twins do not have situs inversus, so an X-ray would not pick up anything unusual. External physical features are the markers for most mirror image twins.

How Rare Are Mirror Twins?

Mirror twins are actually pretty common. Around 25 percent of identical twins are mirror twins, meaning that 25 out of 100 identical twins born are mirror image twins.

This is a fairly common occurrence that is just not well known. That’s why twins can be mirror image twins without even being aware of it.

What Are the Odds of Having Mirror Twins?

Around 25 percent of identical twins are mirror twins. You also have a 1 in 250 chance of having identical twins, and mirror twins are always identical.

Can Mirror Twins Be Fraternal?

Mirror twins cannot be fraternal. Fraternal twins come from two separate eggs and do not have identical features.

Identical mirror twins come from one fertilized egg that splits, creating identical twins with features on opposite sides of the body.

Mirror Twins Organs

In most cases, mirror twins will have their internal organs on the same side of the body instead of mirroring. However, in rare cases they can experience a condition called situs inversus

Situs inversus occurs when one twin has organs on the correct side of the body but the other twin has them on the opposite side. The inside of the body becomes a mirror image just like the outside features.

It’s possible to have situs inversus without any adverse issues. If one twin does have organs on the opposite side than what is considered typical, doctors will monitor to make sure there aren’t complications.

Can Mirror Twins Be Different Genders?

Mirror twins cannot be different genders because they are identical twins. Except in extremely rare cases, all identical twins are the same gender.

That means mirror twins will also be the same gender since they are a subtype of identical twins.

Identical twin men wearing sunglasses and pink and yellow shirts facing each other with arms crossed.

Do Mirror Twins Have the Same DNA?

Since mirror twins are also identical twins, they do have the same DNA. The fertilized egg splitting a bit late does not change the status of the DNA.

Do Mirror Twins Have the Same Fingerprints?

Even identical twins do not have the exact same fingerprints, and mirror image twins are a type of identical twins.

Mirror image twins will likely have similar fingerprints since they are impacted by genetics. However, they won’t be identical since the environment and movement in the womb also affects fingerprint development.

Mirror image twins may have fingerprints that swirl in opposite directions, another aspect of the mirroring. The fingerprints will still not be identical.

Do Mirror Twins Have Different Personalities?

All twins have different personalities. Though they share the same DNA, mirror twins are still two separate individuals.

Genetics are not the only factors that control personality, so fraternal twins, identical twins, and identical mirror twins will all be unique.

Even though twins grow up in the same environment, they may not interact with their environment in exactly the same way. Research shows that over time twins may actually grow to have quite different personalities due to epigenetics.

Epigenetics looks at how behavioral and environmental factors can impact the way our genes work. Even identical twins with the exact same DNA won’t have their genes automatically respond the same to outside factors.

Are Mirror Twins Likely To Have Health Issues?

It is possible for situs inversus to cause health problems, but it’s not a given. The twin who has organs on the opposite of the body than they are usually found can live a life without complications.

Since mirror twins are a subtype of identical twins, they are at risk for the same issues as identical twins. Many of these are related to sharing a placenta or premature birth.

Mirror twins are just as likely to have these issues as any other set of identical twins.

There are less severe health problems that may affect mirror twins at a higher rate. These include:

  • Extra teeth
  • Eye misalignment
  • Cleft lip or palate

These conditions do not tend to cause major problems and can usually be managed with surgery or other forms of care.

Can Mirror Twins Feel Each Other’s Pain?

Mirror twins, like any other type of twins, cannot feel each other’s pain. Though this is a long-believed myth, science has yet to prove that twins have any special ability to feel each other’s pain. 

Sharing DNA does not mean having telepathic abilities, though some twins do speak of having a special connection.

Since mirror twins inhabit separate bodies and have their own minds, they cannot instinctively know what the other is experiencing.

Famous Mirror Twins

Since mirror twins are self-identified, it’s not possible to know who is one unless they offer that information. However, it’s easier to find out which famous twins are identical. 

Some famous identical twins include:

  • Tia and Tamera Lowry
  • Jimmy and Jey Uso
  • Cameron and Tyler Winkelvoss
  • Jon and Dan Heder
  • Jeremy and Jason London
  • Brittany and Cynthia Daniel
  • Benji and Joel Madden

Closing Thoughts

Mirror twins are identical twins with a twist. Like every set of twins, they are special in their own way.