about me
blog author
Meet the Author
I'm Jennifer, and I'm an Occasional Genealogist... sort of. For over ten years I've been a professional genealogist. I started researching my own family nearly 30 years ago. Like many of you, I started as an Occasional Genealogist. I had to squeeze research in while in school and while working full-time. Then I got my first genealogy job and for awhile, it was genealogy all the time. Now I have two kids. I do other people's genealogy constantly but my own? Coming up with ways to do great genealogy, despite all the interruptions, is now mandatory.

Read These Posts First

Posts contain affiliate links. See my disclosures page for details.


What is Reverse Genealogy?

image of car gear shift in reverse
vintage photo of children whispering with text The Secret Genealogy Technique No One Taught You Reverse Genealogy

Reverse genealogy can be a really powerful genealogy technique. A lot of people don't know about it or don't use it as much as they could. This post will look at:

  • What is reverse genealogy
  • How to do reverse genealogy
  • 3 power-uses of reverse genealogy

Reverse genealogy is searching for descendants of a person instead of ancestors. This can therefore include searching for living people, even if you start with someone long deceased. It's doing genealogy in reverse from the direction we normally do it. You start in the past and move to the present.

There's no major difference in how you do reverse genealogy research. It's just genealogy research.

Obviously, if you are trying to research living people there might be differences versus researching people from the more distant past but that's just a different type of research, not something inherent to reverse genealogy.

As an example, you can use a census record for regular genealogy (present to past). You find the person of interest living in the household of his/her parent(s). For reverse genealogy, you'd find the person as the parent and research the children listed. Same type of research, different focus.

Most people have done some type of reverse genealogy. The only "secret" is not realizing you can take it farther. There are a few power uses I'll mention in this post. Before we get to those...

Here's something really important you need to understand and this applies to any type of genealogy. But it is key when talking about reverse genealogy.

In genealogy we always start with the known and move to the unknown.

In genealogy we always start with the known and move to the unknown.

There's more to this and it's covered in a separate post but... In order to do reverse genealogy, you have to know about someone who has descendants. You can't just start with an ancestor where all you have is a name.

Some genealogists try to jump to a new ancestor too quickly, regardless if they are researching in the normal direction or in reverse. It really doesn't work when you do reverse genealogy which is why people almost always get started with normal genealogy. Not surprisingly, we usually know more about events and people closer to the present.

Don't get so excited about how you can use reverse genealogy and then frustrate yourself by trying to "jump" to an ancestor you don't actually know enough about. The way to learn more about someone is to start with their relative you do know about and work from there (start with the known and move to the unknown).

You'll see in the first power-use case that you are actually doing this with reverse genealogy. You are starting with the known person and moving to his or her unknown descendants instead of unknown ancestors. It doesn't matter which direction you want to research, what matters is you start with known information.

Reverse genealogy for traditional genealogy

Reverse genealogy power-use #1

Reverse genealogy can be used for cluster research or the "FAN principle." Cluster research is also an amazing genealogy technique you should learn. It works hand-in-hand with reverse genealogy. You can start both techniques as soon as you learn to do genealogy and keep building your skills, pretty much forever. The harder the genealogy problem you tackle, the more cluster research requires reverse genealogy.

The purpose of cluster research is to identify descendants who will have additional and different records. When you get stuck, researching collateral relatives can provide new research opportunities. Most genealogists begin cluster research by researching in the same generation as their last known ancestor (they research the siblings). Alternatively, your ancestor may be unknown but you know he or she is the niece/nephew/cousin of someone known (i.e. a relationship besides parent/child).

Looking for a quick way to learn more about cluster research? This "quicksheet" by Elizabeth Shown Mills, CG, is a portable reference you can keep on hand no matter where you're researching.

If you try to stay within the same generation, researching siblings, then cousins, then second cousins, etc., the farther removed the relative, the less helpful they become and usually you can't identify these relationships. They share progressively farther and farther removed ancestors (they share the unknown ancestor, then his/her parent, then grandparent, etc.). Your only choice is reverse genealogy.

For reverse genealogy, identify descendants of the known relatives in the generation you're stuck on. Usually, you start by identifying the other children of your last known ancestor. Next you expand to the siblings of the last known ancestor (that's moving a generation into the past, again). Then you research their children (moving a generation to the present, again but now you're researching the nieces and nephews instead of the children). Now you have a cluster of collateral relatives. You can do reverse genealogy as far as is helpful for your project.

The descendants will become farther and farther removed in relationship to you, but they are still the descendant of your problem ancestor. Just because you wouldn't invite them to the family Christmas doesn't mean they aren't useful for genealogy.

You can learn more about any of the three terms as they are nearly synonymous: cluster research, FAN club research, collateral research. Although cluster research involves non-relatives, by starting with a bit of reverse genealogy, you can more easily expand your cluster since you can build a cluster for any of the collaterals, all of whom are descendants of your target unknown ancestor.

There are several uses of reverse genealogy if you're working on a DNA project.

Reverse genealogy for genetic genealogy

You might want to try reverse genealogy even if you aren't interested in doing genealogy research for the sake of genealogy research. If you're working on a project where you're trying to use DNA to find a recent unknown relative, reverse genealogy is usually needed. Non-genealogists might do this naturally as reverse genealogy matches their interests. If you're a genealogist trying to help someone use DNA to find a recent relative, make sure you use reverse genealogy as appropriate.

Reverse genealogy power-use #2

All the talk about using DNA for genealogy has gotten lots of people interested in solving 20th-century problems of parentage. Genetic genealogy (using DNA testing for genealogy) is perhaps the number one reason people consider reverse genealogy.

No matter why you're considering using DNA, reverse genealogy is important.

Genetic genealogy requires your test to be compared against other tests. All testing companies offer the option for you to compare your results against all the results in their database (all the results with permission for "matching"). You have no idea which matches you'll get or how helpful they will be.

If possible, it's better to (also) handpick additional people to have tested to see how their results compare.

To find new test subjects, you can use reverse genealogy. This applies to any type of DNA test. The difference is in who can be tested (male or female and if they are in the appropriate line for the type of test).

Identifying new test takers is a type of reverse genealogy many people can try, even if they aren't experienced as genealogists. You can rely on talking to your known family or DNA matches ("talking" can be communication in any format. This often starts with email if you don't personally know the person. Keep in mind, you may need to cultivate and authentic relationship with them to get them to take a DNA test. That can mean taking your communication beyond just in-personal emails. Reverse genealogy can be hard no matter what form your "research" takes.). 

If you're not a seasoned researcher, reverse genealogy can be done by gathering information from living people. In the past, that's how we always started genealogy, it's just gotten lost with the ease and anonymity of the Internet.

RELATED POST: New to genetic genealogy? Read Best DNA Test for Genealogy

Reverse genealogy power-use #3

This final example of using reverse genealogy is better suited to genealogists rather than non-genealogists because it requires a lot of genealogy research, just in reverse (past to present instead of present to past). It can be used by anyone working with DNA, though.

There are two phrases I'd use to describe what you want to use reverse genealogy for in this third power-use case. One is building DNA trees. I've written about this many times so I don't discuss this use specifically as relates to reverse genealogy. Here's a post about why you must build DNA trees if you want to use DNA for genealogy.

The other phrase is one I pretty much had to make up because it's just a variation of building DNA trees. I've called it "pre-finding lineages." Often when you're encouraged to build trees for your DNA matches, you are starting with the match and doing genealogy from present to past. You need a tree for your matches. When you get stuck, you likely use some reverse genealogy but "pre-finding lineages" is essentially the reverse concept using mainly reverse genealogy.

I talk about pre-finding lineages more in-detail in the follow-up post but to summarize, a not-to-be-missed use of reverse genealogy is starting with the ancestor you want to focus on and doing reverse genealogy. Research his/her descendants so you already have the trees of potential matches built. This can save huge amounts of time and sometimes is far more successful than trying to start with the match and work in the normal direction (into the past).

So that's it!

What is reverse genealogy? It's researching from the past to the present. How do you do it? Just like any other type of genealogy.

The tree power-uses for reverse genealogy are:

  • Collateral/cluster/FAN club research (identify the descendants to expand your traditional research opportunities).
  • Finding DNA test-takers for specific projects.
  • Building DNA trees from the ancestor to his/her descendants (to save time when connecting matches or to make it easier to identify lineages of matches).
text the secret genealogy technique no one taught you text the secret genealogy technique no one taught you text the secret genealogy technique no one taught you text the secret genealogy technique no one taught you text the secret genealogy technique no one taught you reverse genealogy