Identical Twins: 5 Things Parents Need to Know

Identical twins are a phenomenon of nature. Yes, we know how they are formed—one egg fertilized by one sperm and then magically the single egg (or zygote) splits into two—but we still don’t know why it happens. Unlike fraternal twins that tend to run in families, identical twins do not. They’re still a scientific mystery. Furthermore, the special relationship that identical twins share is equally mysterious, a source of intrigue and fascination not only to the world around them but to their friends and family as well. This week I’m ending the “5 Things Parents Need to Know” series with identical twins. (You can read about fraternal twin boys here, fraternal twin girls here, and finally, opposite-sex or boy-girl twins here). Just a reminder: these are general characteristics based on twin research—your identical twins may be completely different.

  • Blonde twins in field of sunflowersIdentical twins are the most cooperative of all twin subgroups.

Identical twins as a group have an easier time sharing possessions. They quarrel less, and show more emotional support to their cotwin than fraternal twins do. Furthermore, they enjoy playing with each more than playing alone unlike fraternal twins who sometimes choose to play solo.

How is this knowledge helpful?

Who wouldn’t love watching their kids playing peacefully together? And, sure, you’ll have fewer toy wars when your identical twins are toddlers. But don’t get complacent. Remember, all children need to learn how to socialize with other kids so why not enroll your twins in preschool or a play group where they’ll get ample practice negotiating and articulating their needs to others?

  • Identical twins often look less alike at birth than fraternal twins.

It’s crazy but true. The prenatal environment (i.e. twins developing in the womb) is far more different for identical twins than it is for fraternal twins. Thus when they’re born, identical twins often look nothing like each other.

How is this knowledge helpful?

Think your twins are fraternal simply because they looked so different at birth or because the doctor told you they had separate placentas? (FYI…30 percent of identical twins have separate placentas.) You may want to have them tested. It’s cheap, easy and the only true way to determine zygosity. And you may just find out that they are in fact identical.

Please note: DNA will eventually take over—as time goes on, identical twins will slowly begin to resemble each other more and more while fraternal twins who looked liked two peas in a pod at birth will begin to look increasingly different. It just may take a few years.

  • Identical twins are closely matched on intelligence tests.

Most identical twins score within five points of each other on IQ tests. Fraternal twins usually score farther apart (nine points, on average). Single-born children in the same family, however, can have a difference of 10 to 14 points.

So how is this knowledge helpful?

If your twins share the same classroom, their schoolwork, homework, projects and tests may at times appear exactly the same! Although it may be fascinating to you, your children’s teacher may suspect collaboration or worse, cheating. Therefore, it’s always a good idea to go the extra mile to make sure your twins work separately not only to avoid the appearance of plagiarism but so that each child can develop at his own pace and pursue his own individual interests.

  • Identical twin girls use their twinship to their social advantage.

More than any other twin sub group, identical twin girls realize that their unique relationship puts them in the spotlight. Once they make this discovery, many often highlight their similarities to draw more attention to themselves, increasing their popularity. In other words, they use their twinship to make and maintain friendships. However, when identical twin girls enhance their similarities rather than celebrate their difference, it may affect their sense of autonomy as they become more dependent upon each other for their social survival. Social psychologists and twin researchers call this the prima donna effect.

So how is this knowledge helpful?

From day one, encourage each girl to be her own person. From separate wardrobes and accessories to after-school activities and solo play dates, be an advocate for their individuality.

  • Identical twin boys tend to be the most introverted out of all the twin subgroups.

Identical twin boys tend to be more socially shy, less talkative and often hesitant in new social situations when compared to same-sex fraternal twins or their single-born counterparts. Furthermore, unlike fraternal twins boys who are usually very insistent on their individual rights (“Hey, that’s my toy!”), identical twin boys are not.

So how is this knowledge helpful?

Although there is nothing wrong with being shy (I’m married to a shy man), some twins withdraw and only feel comfortable when associating with their cotwin. However, you can help build your twins’ confidence by offering plenty of play time with other kids. Direct contact with other children in a relaxed setting is how they’ll learn to effectively negotiate and problem solve. In time, each boy will learn to speak up for himself.

At home, give each boy separate responsibilities or age-appropriate household jobs, too. Helping around the house will make him feel useful and important. And don’t forget to offer lots of loving praise when they complete their tasks.

Finally, gently teach your boys simple social graces like making eye contact, smiling, and shaking hands. A great way is to role-play with them at home by play acting simple social situations—how to join a group of children on the playground, for instance.


4 thoughts on “Identical Twins: 5 Things Parents Need to Know

  1. Tim Johnson

    “Identical twins are the most cooperative of all twin subgroups” (?). Huh? Guess my identical twin girls forgot to read up on that study! We generally have issues around sharing, taking turns, one girl grabbing things from the other girl, etc. One girl likes to have her “things” neat and orderly and in place, and the other is Shiva the Destroyer, who cares not about neatness and order, but only about destruction and disorder. Shiva also seems to delight in goading her sister and getting her to be upset or cry. We have tried many things – time-outs, demonstrating “trading” items, and even sometimes setting a timer or “counting” for who gets an item for how long (the counting also becomes a natural play “lesson” where we also count in Spanish or English). Thus far, however, the counting has gotten us as parents more involved in negotiating the peace or refereeing disputes than I would like. Ultimately, I would prefer the girls take turns “counting” on their own or otherwise working out their own peace treaties. Christina, somewhere in here is a great idea for your next article – how to help uncooperative twins independently problem-solve!

  2. Angela

    I can not agree that they don’t run in families! I have ID uncles and then 9 yr old ID boy cousins, my girls are ID TTTS survivors and four months later my cousin had ID girls . On my mothers side I have two sets of ID boy cousin and one set of girl/ boy fraternal. None of us used anything All natural . One more on my dads side another cousin who was six month with ID but they past away in uterus do to a fall when moving. So no one used drugs and there are all these ID sets .

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