I think all babies look alike, even when they are not identical. I need to come up with a strategy over the next few months.

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    The evil one will have a goatee and sinister laugh
    – dave
    May 19, 2011 at 3:56
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    @dave No, the evil one is the one that describes his brother that way. :)
    – Iterator
    Oct 22, 2011 at 12:52
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    Invest in tattoos
    – DA01
    Oct 24, 2011 at 14:33
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    Look for moles. You could also shave a tiny line in one's hair until you develop that normal parental skill of just knowing who is who. Baby hair takes like a full year to grow into something that can even be styled at all, which is probably enough time to identify some other guaranteed way to tell them apart. I'm assuming DA01 is joking about the tattoo thing, but I don't have twins. My daughter is friends with twins and it was very hard to tell them apart for years until I was told one has a tiny mole on her neck. Aside that mole, impossible to tell. And they love making you guess
    – Kai Qing
    Apr 27, 2015 at 22:29
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    @tomjedrz You can increase the effectiveness of this approach by also giving them the same name. That way, you're never wrong Mar 1, 2020 at 13:33

6 Answers 6


My wife and I faced this very issue with our twin boys, now four years old. When we first brought them home from the hospital, we kept the little wristbands on them for the first few weeks, until they started to outgrow them. Then, we painted their big toe a different color so that we had a foolproof way of keeping track -- the nail polish wouldn't come off easily, and even when it did start to come off, it would generally leave traces of the color for a while. After a few months we managed to identify tiny differences (small moles, different patterns to the way their hair swirled, etc.) that we could use, and once we were confident that the differences were there to stay, we stopped painting their nails.

I studied philosophy in college and my wife is a linguist, so besides being two people from professions that should never be permitted to raise identical twins (physicists being another group that should also be so banned, since their textbooks are similarly filled with "thought experiments" that would more aptly be characterized as "twin torture") we were also quite obsessed with the existential implications of how names work, and what happens if they get mixed up.

If you do go with the nail polish approach I'd definitely make sure to get a brand that's non-toxic and to not over-do it because little growing nails do need to breathe -- you might want to switch up which nail you paint each time. Also -- and this is very, very important -- you need to reach an agreement with your partner that neither of you will ever, ever, EVER "play a joke" on the other and switch them on purpose. :)

  • We brought nail polish in case our twins turned out to be identical. It turned out we didn't need it (they looked very different, obviously fraternal), but I'm glad it was there. We also tended to dress them in different colors - both girls, I. was dressed in yellow and green, and L was dressed in purple and blue. This helped our relatives tremendously. May 25, 2011 at 19:08
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    I guess you mean psychologists instead of physicists. Physics involves very little twins, where psychology loves them. Oct 30, 2011 at 19:46
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    Oh no, he means physicists. We like putting one twin on a rocket ship and leaving the other one behind. Then we get the one on the rocket ship back to earth and we obsess for decades about which one should be older. It sounds odd when you put it like that, but trust me there is method to the madness ;)
    – drxzcl
    Nov 11, 2011 at 0:36
  • This was the strategy we followed with our identical girls as well. I don't think they're all that identical any more (3.5y) but other people tell me they're hard to tell apart. Maybe I just remember how I dressed them in the morning?
    – pjmorse
    Oct 8, 2014 at 1:15
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    "little growing nails do need to breathe" [citation-needed]
    – bjb568
    Apr 26, 2015 at 16:21

Not a parent of an identical twin here- but one myself. My brother and I are so identical that even our parents and five (yes, five) older brothers can't tell us apart quite frequently. Of course, we purposely wear similar clothing and are very similar in personality, as well.

When we were born, our parents were prepared for twins and actually just grabbed a nontoxic marker and drew a little star right on my brother's (the older one) hand, and kept it that way for several months.

An unrelated fact is that for some reason, we have the same first name. And actually go by that name half of the time, though we do use our middle names as well.

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    Having the same first name as your twin? Now that is cruel. :)
    – Anoplexian
    Dec 9, 2016 at 16:32
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    I'm really curious to know how you came to share the same first name! Who thought of that, and why!
    – learner101
    Apr 17, 2017 at 4:29
  • @learner101 And I thought my comment above under the question was a joke! Meanwhile, I do know someone of a Filipino background who shares the same first and last name with four siblings. They go by different pet or middle names, but she constantly has trouble identifying herself at banks and whatnot when signatures, photos, and life details don't match records! Mar 1, 2020 at 14:30

Even identical twins aren't exact copies of each other. There ARE differences!

Look for these differences, however small, and remember that Bob is the one with the narrower toenail, and Ben was born with longer hair. Alice has a dimple on the left butt cheek, Denise has one on the right shoulder.

If all else fails, you can still mark the twins as @Bill explains.

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    While that is true, it takes a while to learn to tell the differences. Until then, the dab of nail polish is a great idea.
    – cabbey
    May 20, 2011 at 7:48
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    Lots of these small things are really hard to spot on the fly, though. I can tell our girls apart if I hear them talking, but if I see them running at me and just saying "Daddy!" I'm not going to know who's who for a few minutes - and I'm not going to be able to check for moles.
    – pjmorse
    Oct 8, 2014 at 1:17

To add to the above comments use clothing colors and patterns. The following list developed over time, often based on what colors the our boys were drawn to at a young age. Since about 3 months old Twin B always reaches towards the yellow toys and clothing.

In our house it is an unwritten rule that:

Twin A always wears blues, greens, browns, solid colors, and/or anything with puppies, trucks, or superman on it

Twin B always wears yellows, reds, oranges, stripes, and/or anything with monkeys, sports equipment, or batman on it.

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    We follow a similar rule, although we don't prevent our boys from picking the "wrong" colors if that's what they pick out to wear... which results in those being pretty confusing days for us and their teachers. :)
    – Bill Clark
    May 25, 2011 at 17:52
  • Even now when they are only a year it gets confusing when someone puts that SuperMan pjs on the wrong boy. :) May 25, 2011 at 18:07

When the twins are first born and their footprints are made, these are one of your best guarantees of uniqueness. These will also be a treasure for your children, so keep these and perhaps make new ones over time. It takes a moment and it's much easier than stressing over how they are dressed or otherwise decorated.


I have triplets, two of which are identical. It is incredibly unlikely that it will be impossible to tell them apart. If they share a placenta it is likely that they will be born with different weights and will always be slightly different.

After mine were born the smaller one was intubated once and had an umbilical vein catheter placed - so the cry (voice) is different and the navel is different. It didn't take long to find a lot of differences, such as freckles. Babies are also usually born with skin blotches created in the womb that fade later. One of our identicals had a huge dot on his forehead.

When they are born just inspect their skin very carefully and you will probably find distinguishing marks. Otherwise go with the markings.

When they are old enough give them different haircuts. We had one long, one short for a very long time until they wanted the same haircut shortly after turning five. They're still five and we're tired of that - they are getting disssimilar haircuts as soon as possible.

One thing that always concerned me was nail polish. Some nail polish has chemicals that are teratogenic - as in causing birth defects. I wouldn't use anything like that on a newborn.

If you do use markings, use something that will survive a bath.

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    Would you be concerned with teratogens once the baby was born (presumably normal)? Or are you worried about the mother possibly becoming pregnant again and being exposed to nail polish? Apr 17, 2017 at 14:50
  • So if you are worried about nail polish chemicals, use "piggy polish" (that's the name we had for it) It's all natural for small children. You could eat it without ill effects. Feb 29, 2020 at 15:32

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