Identical Twins Personalities Switch

Joe Rawlinson by Joe Rawlinson - September 17, 2009

Which is which?
We’ve got identical girls and often rely on their mannerisms and personalities to tell them apart.

If you rely on this too, or hope to, be careful: twins switch personality traits at will.

For example, one of our girls will be shy one week while the other is a social butterfly. Just when you think that is the pattern, they switch and the social standout now cries hysterically with strangers. Go figure.

We’ve seen switching of twin personalities and traits even at an early age in all these cases:

  • who is a good eater
  • who is a wiggle worm
  • who wakes up first
  • who takes good naps
  • who drinks her bottle in one sitting
  • who smiles at strangers
  • who makes what sounds (our girls aren’t talking yet)
  • who steals toys from the other

So if you want to keep your twins straight, particularly if they are identical, combine multiple data points in identifying each. Combine personality traits and even subtle visual clues to properly identify who is who.

It is fascinating to watch the switcheroo happen. Just keep your eyes open and enjoy the journey.

(RELATED: Your twins will need a lot of gear. Here's the complete twins baby registry checklist to get ready for your twins' arrival.

Further Reading

Dad's Guide to Raising Twins book
Don't forget to pick up a copy of the definitive guide to raising twins. "Dad's Guide to Raising Twins" was written for fathers of twins to help guide you through the first several years with twins. Click here to learn more about the book and get your copy.

24 thoughts on “Identical Twins Personalities Switch”

  1. I’m noticiing this more and more as my identical twins get older. It’s getting more and more distinctive, and lasts from 2-3 weeks everytime…. then they just snap back.

    • @Danielle – thanks for sharing the experience with your twins. Each of our girls has some core personality traits that remain constant but they definitely still switch other characteristics back and forth.

  2. This is SOO true!!! We are experiencing it as we speak! For the umpteenth time, our identical twin girls are acting opposite each other and it is crazy!

    I dread it because it messes with my head when they do and it seems so intense when it’s opposite actions!

  3. oh Wow! My identical twin grandsons switch personalities regularly. One will brood while his brother socializes, then the other will get his brooding time in while his brother is socializing. We just go with the flow. If I am around them I can tell them apart. I have no clue how I do it, there is obviously something that I’m subconsciously aware of with each of them. However, now that they are older and don’t require as much of grandma’s gushing over them and preferring High School activities instead, I am embarrassed when I ask them “what is your name,” and they smirk and tell me their name. Once they tell me their name my “subconscious twin indentifying mechanism” kicks in, and I know who is who. It’s always so much fun! 🙂

  4. My twins are doing this as Im reading this. I can tell the day it happens because they are so opposite. It usually lasts about a week.

  5. This is not an identical twin thing. Our fraternal twins do the same thing, which is how I found this website- searching for answer as to why. It drives me nuts.

  6. My identical 2-year-old girls do this. But for long stretches at a time. For a long time, twin A was more assertive, aggressive, less obedient and more outgoing and twin B was docile, more passive, super sweet. And literally the week after we had our first parent-teacher meeting where we discussed Twin A’s challenges in the classroom, they switched personalities and have been that way ever since. It is trippy. Keeps us on our toes and is very confusing.

    • @Darragh – that is interesting timing (right after the teacher meeting). It is like our twins know we are strategizing ways to parent/teach them and they change things on us to keep us off balance.

  7. So our guys used to do this… then things settled for several years. Just now (age 16!!) it happened again! This week, the rude cranky one had become kind and loving, and the one with whom I’ve really bonded over the past few years had become disrespectful and distant – It is the weirdest thing! Now we’re working to bring the despondent one back into the folks while enjoying newfound cuddles and love with the other. 🙂

    • @Vera – thanks for sharing what is happening with your twin teenagers. It is interesting to see that this pattern continues even as the twins get older.


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