Why I Like MyHeritage’s Theory of Family Relativity for DNA Matches

Diahan Southard

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MyHeritage’s Theory of Family Relativity reconstructs possible family trees between you and your DNA matches. Here’s why I love the way they’re doing it.

MyHeritage* released its Theory of Family Relativity tool at RootsTech 2019. They call it “a total game-changer in genetic genealogy,” and it is.

MyHeritage’s Theory of Family Relativity

The company explains the Theory of Family Relativity in a nutshell:

“We provide you with leads explaining the relationship between your [DNA] matches based on our entire collection of family trees and historical records, removing the guesswork, and saving you hours of research time. You can then examine the theories and the information associated with them and verify their correctness.“

Rather than trying to piece together your tree connection to your DNA matches by just what’s on your tree and theirs, the site creates plausible trees based on ALL their trees, PLUS their historical records—PLUS tree data from the enormous community trees at Geni.com and FamilySearch. It’s basically the most massive tree hinting system ever.

Here’s what it looks like (I’ve taken an example from the MyHeritage announcement and marked it up since the type is so small—click on the image to enlarge):

MyHeritage Theory of Family Relativity DNA matches.jpg

MyHeritage calls this a “tree traverse system,” since it essentially threads you through potentially several different trees to connect you to your match.

These are THEORIES, and MyHeritage expects you to confirm the possible trees yourself. They’re only accurate insofar as the various trees and records are accurate and actually belong to your ancestors. But MyHeritage makes it easy for you to check their work. See the green circles above? Those are all points of connection between one source and the next. Those are CLICKABLE. The idea is that you’ll verify each connection yourself.

“The number of theories you may get depends on several factors, such as the size and level of detail in your family tree (the more the better),” says MyHeritage in its press release. “This number will increase over time as more users test their DNA on MyHeritage or upload their DNA result, and as we continue to add more historical records and as family trees continue to grow.”

Update in February 2021: A recent update to the Theory of Family Relativity increases the total number of theories to nearly 40 million (more than 27 million DNA matches have at least one theory).

Find your MyHeritage Theories

If you’ve tested with MyHeritage DNA or uploaded your DNA, you may have some theories waiting for you to view. While they’re not available for every match, you’ll find multiple Theories for other matches. Those additional Theories are listed as Paths that you can click on to review.

Theory of Family Relativity Path.PNG

You do need to have the right site subscription (Premium, Premium Plus or Complete Plan) to fully access the Theories. If you’ve uploaded your raw DNA to MyHeritage from another testing service (which is free), you can pay a one-time fee of $29 per kit to unlock all the site’s advanced DNA features, including the Theory of Family Relativity. According to the site, “users without a subscription will still see all theories that we found for them, but when they click to see the full theory details, some of the information will be hidden.” Another option is to take advantage of MyHeritage’s 14-day free subscription trial if you’d like to “try before you buy”.

Transfer to MyHeritage

Ready to look at your Theories? Log in and go to your DNA homepage. Look for this banner and click on it:

You’ll also see clickable notations on your match list next to those matches for whom theories have been generated. Review the theories carefully, remembering that theories are built off tree and record data alone, NOT using your genetic relationships (other than the fact that you are a match). MyHeritage recommends that you ”compare the relationship suggested by the theory to the relationship suggested by the DNA to see if they are compatible.”

MyHeritage+3rd edition.png If you’re just getting up to speed on MyHeritage, you’ll likely find my MyHeritageDNA quick reference guide very helpful. This guide covers the basics of MyHeritage: what you’ll see when you log in; a detailed explanation of the tools on the match page; and pointers on how to use your ethnicity results, which continue to be important because those Theories, while great, won’t solve all your DNA match mysteries.

Take me to that Quick Guide!

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<a href="https://www.yourdnaguide.com/author/guideyourdnaguide-com" target="_self">Diahan Southard</a>

Diahan Southard

As founder and CEO of Your DNA Guide, Diahan Southard has been teaching people how to find family history answers in their DNA for several years, and she's been in the genetic genealogy field since its infancy. Diahan teaches internationally, writes for popular magazines, consults with leading testing companies, is author of Your DNA Guide–The Book, and producer of Your DNA Guide–the Academy, an online learning experience.


  1. Stan

    I suggest you take a closer look. Each link from one tree to another is assigned a probability. Setting aside the question of how this assignment is made, note that the probability of the correctness of the complete chain should be the product of these individual link probabilities. But My
    Heritage/23andMe reports instead the smallest of the link probabilities. This can make a big difference. For example If there are three links with 70%, 50%, and 40%, MyHeritage/23andMe will report 40% for the overall probability, whereas the correct value is 14%. It is NOT a matter of a chain being as strong as its weakest link!

    • Diahan Southard

      Stan, interesting point. Not sure why you are bringing in 23andMe here, as that is a totally separate company that does not have this tool, but that is beside the point.
      I concede that in statistics the overall likelihood of a situation would be obtained by multiplying the individual probabilities. But I don’t think that is what they are going for here. They are assessing the likelihood that the genealogy connection point contains the same data, not trying to predict an outcome. So it isn’t a probability in the mathematical sense. So the higher the percentage, the more confident MyHeritage is that you have the same person because the name/place/parent data is the same.
      So maybe the percentage reported feels a bit misleading, as it feels like it should be probabilities and likelihoods, when really it is just a simple assessment of overlapping data.

  2. Cynthia Lyons-Dailard

    I think 23 & Me came into Stan’s comment because you said it in your explanation. It confused me a bit too, as I thought you were referring to My Heritage only. Might want to listen to your recording to see where the confusion comes in.


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