What do my siblingship DNA test results mean?

One of the most common searches that people find my blog through is siblingship DNA tests. In the past few months I have received MANY emails from adoptees and donor-conceived adults who have gone through a DNA test with a possible sibling - only to receive results they don't really understand. Some simply do not understand what their results mean. Others are confused as to why they are inconclusive. Many others think that there's still a possibly of them being siblings when in reality the results are VERY negative.

Most just want the peace of mind of knowing if they are siblings or not. For most of these people I am able to give them some concrete answers or lead them in a direction to provide them better results.

This shows me that most DNA testing companies are doing a less than satisfactory job at explaining what an individual's results mean in plain language --- a catch that many in the medical field struggle with. Medical information to the layman means nothing if they cannot comprehend what they are being told or reading.

So I thought, rather than talking about DNA testing in general or what all the different numbers mean, I wanted to discuss negative and inconclusive results as well as postives and provide some examples of these types of results as well as how DNA testing companies word results (that make them indecipherable to those without background knowledge).

Below are some examples of actual DNA tests (names have been removed to protect the individuals) with some explanation as to what they mean.

Example #1: Conclusive sibling match w/ both mothers tested.

Below are results of a siblingship DNA test with two alleged siblings and both their mothers that is clearly a conclusive match.

In the above example the two alleged siblings and both their mothers were tested. When both mothers are tested it allows the analyzers to determine which allele at a specific marker came from the alleged shared biological father. If the two alleged siblings share this allele it increases the individual SI for that marker. The results are in the yellow box below. This is very obviously a sibling match as they are 99.8% probability of being siblings. The CSI (combined siblingship index) is over 500, signifying a very strong conclusive result. No questions asked, these two individuals are most definitely half-siblings.

However, as I show below, even in the case where two individuals are most definitely siblings in one test, take away the mothers and those results change dramatically!!

Example #2: Inconclusive sibling test w/ neither mother tested.

If we took the same two siblings in Example #1, but neither of their moms were tested, here's what we would have...

The same two individuals that in Example #1 were surely siblings, these results are questionable, and would be considered inconclusive. They cannot be deemed negative because they are between 0.5 and 1.0 (although nearly on the brink of going below 0.5). Their probability is only at 33% but their odds are 1.95 to 1. That is....they are 1.95 times more likely of NOT being half-siblings than being half-siblings. These odds, while still suggesting inconclusive negative results, are still fairly low.

Odds that are more like 20 to 1, 50 to 1, 100 to 1, are more significantly negative results. A result received like in Example #2 suggests to me that further testing should be done.....especially if one or both mothers were not tested!!!! If both mothers ARE tested, I would suggest a second panel of STR markers (autosomal markers like the ones above...most DNA testing companies can do extra if you request them) or either X or Y chromosome testing (if the two alleged siblings are of the same sex). The latter is preferable for same-sex alleged sibling pairs.

Example #3: Inconclusive sibling test w/ one mother tested.

Here is another example of an inconclusive result. In this case only one mother has been tested (as can be often the case with older offspring and adoptees where one mother may have already passed away).

The results suggest relatedness, as in the CSI is over 1.0 and the probability is over 50%, however it is only over the threshold by a smidgen.

The two examples I showed above provide reason as to why I STRONGLY suggest at least one mother to be tested!!! I know there are many siblingship tests that are found to be inconclusive or downright negative when in fact they may actually be siblings, simply because neither mother is tested. In Example #2, these two individuals, if one of the mothers were tested, their results would have been at 92% probability - enough for the US Courts, but would not have been successful with UKDL's stringent 99% cut-off. In Example #3, had it been possible (one mother was deceased), a further test taking into account Sibling 2's mother could possibly have provided these two individuals the peace of mind of knowing that they were or were not truly siblings. I suggested further STR marker tests for these two.

It's this probability and odds that confuse many people, and are what constitute the majority of questions I receive. Remember: Siblingship tests are based on a prior probability of 50%. This means that 50% probability is the starting point and and results that lean towards being positive will raise that probability above 50% and results that lean towards being negative will lower that probability below 50%.

Some people are confused and this that a probability of say 20% means the probability of two individuals being siblings picked from random - i.e. 20% with zero as the starting point. This makes a 20% probability sound relatively supportive. However, when a siblingship test is being conducted, they are already under the assumption of being possibly related and not random individuals, thus the prior probability is 50% (there's a 50-50 chance that they are or are not related). Therefore, a probability of 20% is NOT good.

Example #4: Conclusive negative sibling test w/ both mothers tested.

Below is a conclusive negative test, with not questions asked these two individuals are not related at all.

In this example these two individuals are conclusively not siblings. With results like these it would be nearly impossible for further testing to provide anything but similar negative results. The combined siblingship index is waaaayyyy below 1.0, and the odds are over 1,000.

I hope these examples and their explanations have helped many of my readers and those that find my blog for these questions, to better understand your results, and have more confidence in what they mean. As always, please email me if you have any further questions or would like me to take a look at any results and provide a better understanding into what they mean.

Stolen gametes....sounds like baby trafficking to me

So I read on the AmFOR registry today of a woman seeking information regarding an incident almost 20 years ago involving her getting a hysterectomy and the doctor stealing the ovaries and selling them....at least that is what I am inferring from her post.

While I do not have any proof or further information regarding this exact situation, it made me think of what could really be going on illegally in the infertility industry. The industry has been famous for being unethical and pushing lies and deceit. I suppose if we think in this manner, it would not be unusual to believe that this same industry would work in more illegal ways to make money.

The beginnings of donor conception began with deceit and what would likely today be considered illegal -- i.e. performing a procedure on a patient and not informing the patient of what was done. So if that is how the industry was founded, I would not be surprised if they've found new more novel ways of continuing this tradition. A woman goes in for a partial or full hysterectomy. The doctor removes the ovaries, yet instead of simply destroying them (or whatever they do with them after they are removed) he decides he's going to extract the eggs and sell them or use them in his own infertility practice.

This patient, who believes she has simply had a hysterectomy has no clue that her eggs, her biological children, are being implanted in other women.

I know it seems very sci-fi and ridiculous, but take a minute to think about the mentality of the infertility industry....... Do they care about their patients? NO. Do they care about the offspring created? NO. Do they care about the donors and their rights? NO. Do they care about making money? YES. So now the doctor has perfectly good eggs harvested and does not even have to pay the woman for her "services", and he can charge someone outrageous IVF fees to implant them and make even more money!!

They would probably shake it off as that woman was being altruistic (which one cannot be if one does not know of the situation) and that the children will never be told who the donor is so the woman will never know and the social parents will never know, and all's fair in love and war! And everyone is so HAPPY!!!!

I ask my readers: What are your thoughts on this possibility? Do you think it's happening or do you think this is all made up and over the top? What should be the legal implications involving non-consensual gamete donation? Do you think that males could be taken advantage of in the same way?

Donor Offspring DNA Database - UPDATE!

Good news!! I learned the other day that we may have found someone to help us create a database to store and compare donor-conceived offspring and donors for sibling and paternity matches! Even better is that he is another DC offspring...Adam, an Aussie offspring has a background in IT and programming and is interested in helping us devise a program that would enable registered users to upload their CODIS markers (the 15+ markers used in siblingship and paternity DNA testing) and find potential matches that score a siblingship index over 1.0 (50% probability of relatedness).

Again, even though this database is not yet created I am happy to take any offspring (or donors) DNA results and add them to our growing list which I will manually scan for matches for the time being. Remember, the more people in the database means the more likely you will find a match! Like UKDL, this is going to take years likely, before we actually find success, but Damian and I are confident that with such technology and accessibility available, the chances of adult offspring finding relatives will be greatly increased!

Please email me if you are interested in contributing your DNA results.

PLEASE NOTE: We are not capable of performing the actual DNA test!!! Email me and I'd be happy to recommend several DNA testing companies that I have personally worked with.

What we are trying to provide is a way to eliminate the unnecessary multiple-testing of individuals trying to find their donor families.

For example, I did 3 paternity tests (all negative) and one siblingship test (negative), but I received results for each of these tests. My mom was tested on the siblingship test, which provided her alleles and thus by process of elimination the allele inherited from my donor was deciphered. When I was contacted by my [now] half-sister's mom with her DNA tests from 2 paternity tests, I compared both of our results and was able to determine with considerable accuracy that she and I held a probability of being siblings upwards of 90% - and this was with several marker alleles missing in the original tests! This led us to perform a true professional siblingship DNA test. When the results came back we were considered sisters with 99.8% probability!

We want to provide a way to save individuals money, time, and heartache, by performing the calculations on previous DNA samples to determine if there is even a chance in hell that the two said individuals are related. We promise to inform any individuals that score over 50% probability (combined siblingship index of 1.0) of their potential match. This is because we understand that siblingship tests are inherently inconclusive, and it should be up to the said individuals to determine if they need extra testing, or want to exclude the possibility of being siblings.

See previous posts regarding what DNA tests are in general (Whatcha gonna do with all that junk in your...DNA), and more about siblingship tests and what all the numbers mean (To test or not to test...DNA half siblingship tests, and Even more about DNA half-siblingship tests)

Remember: United States Court of Law states that a probability at or above 90% is considered admissible in court. The UK DonorLink holds a much stricter view, at 99% probability. Thus, individuals who are a part of the UKDL project may in fact have a match with whom they have NOT be informed of!!!

"Connect" to another new offspring blog!

A relatively new blog (at least new to me) was pointed out to me today and I wanted to pass along the link.

Connect It is the story of a 28 year old donor-conceived adult, who has known of her conception for 5 years. Conceived from Dr. Decker's office on Park Ave in NYC in the early 1980s, she talks about her thoughts, frustrations, and even the humor, that are a part of the lives of those of us searching for our kin and our identity.

I look forward to reading more of this blog in the future! So glad to be seeing some new faces in the DC blogosphere, taking up the offspring POV - it's been a long time coming, but the revolution is beginning. Just wait until all these lil ones of all the DSR mommies come of age.....revolution is not even going to begin to explain the changes we'll make!!!

New resource to search for donors using yearbooks!!

Last month I was passed along this website, and my life has been so busy that I just now got a chance to take a look at it. This is definitely a keeper.

For anyone who has already used yearbooks in their search, they know that looking through yearbooks is a great way to narrow down a search, and this new resource is fantastic for those who are not in the locale of either where their conception took place or where their donor donated.....or simply cannot afford or find a yearbook(s) from the year(s) their donor was at that school.

It's called E-Yearbook (http://e-yearbook.com) and it provides complete coverage of high school and college yearbooks for a select number of institutions across the country (only a couple outside the US though). The cost is $29.95 for a year subscription with unlimited access....or $4.95 per month (but you must subscribe to at least 4 months in advance).

Even on eBay many university yearbooks sell for upwards of $100 or more, so this is an excellent opportunity for many offspring to browse their donor's university yearbook to check for resemblances without breaking the bank.

You can search the site to see what schools are covered as of now, and more are likely to eventually join in the future. For example, for me they do not have coverage of the Medical College of Georgia, Augusta College/Augusta State University, so the likelihood of it being useful for me now is low, but hopefully in the future more schools will join.

If anyone has already used this website or decides to join, please let me/us know of any success!