Genetic Sexual Attraction - a couple’s story going viral as a result of a 23andMe test discovery

A story was posted a few days ago on Reddit by someone claiming to have discovered he and his girlfriend are half-siblings, the discovery coming after both opted in to the DNA Relatives feature for their 23andMe test.

Both reportedly knew they were donor-conceived and were on the hunt for their paternal biological families, but apparently neither was suspecting the possibility they may have come from the same sperm donor. The discovery was reportedly traumatic, with the relationship ended same-day and temporary thoughts of suicide mentioned by the writer of the Reddit post.

The veracity of the report hasn’t been confirmed, but if it is, we all must hope the individuals involved have been connected with a counselor or other support. Other reports of donor half-siblings having found each other and unintentionally pairing up have come out before. The resulting psychological impact of such a shocking discovery is evident and understandable on both accounts.

Consumer DNA tests and the world of ‘anonymous’ donors and assisted reproduction

The possibility of accidental incest being discovered (with consumer DNA testing the avenue of discovery) is something those of us in the world of genetic genealogy have recognized as a real possibility and have seen in anecdotal cases. It comes not as a surprise to us; it’s confirmation that more discoveries like it can be anticipated in the future.

Given the questionable practice of repeated use of the same donors in the assisted reproduction industry and variability of legislation surrounding sperm donation from one place to another, it’s almost certain these cases mentioned above are not isolated. In some places, such as Ireland, anonymous donation is being outlawed, as the drawbacks of such a practice have been recognized.

For years, many people have been calling attention to the problem with anonymous donation. It is problematic to keep donor identities hidden/anonymous -- allowing for high-numbered donations from the same person, and along with that, an increased chance of any given donor’s offspring inadvertently meeting and pairing up. The idea of donors remaining ‘anonymous’ is clearly a misnomer in 2019. And the continued use of anonymity in donation of eggs, sperm, and zygotes is not really possible, which some assisted reproduction clinics have started to explain to both customers and donors.

These are issues that may not affect a high number of people, but for those it does affect, the impact is significant and traumatic. This is also an avoidable scenario, if truth-sharing regarding parentage were a requirement, with proper identification and documentation of donors, and sharing of a donor-conceived person’s parents of origins being a given, rather than being an exception to the norm.

 What is GSA and is it real?

 This report of donor half-siblings in a sexual relationship has triggered the discussion about a phenomenon called Genetic Sexual Attraction, or GSA.

First, let’s straighten out some of the terminology so we can all think about and discuss this clearly:

  • Incest - the name for the activity when two people who engage in sexual activity are closely related

  • Accidental or inadvertent incest - incest that occurs when the two partners are not aware of their relatedness until after a relationship has begun

  • Consanguinity - mating between family members, but not close/immediate family (for example, two cousins having a sexual relationship that produces children is technically considered consanguinity, not incest)

  • Genetic Sexual Attraction - a description of the feelings of attraction between those closely related to one another by DNA, whether acted on or not*

  • High ROH - the genetic pattern we see in a DNA test result for individuals conceived from a sexual relationship between close relatives. For more on this topic, see posts I have written here, here, and here.

 *There is no terminology yet (that I know of) for distinguishing GSA that leads to a sexual relationship versus a feeling not acted upon. Thus, the term GSA is being used interchangeably for both the emotional feelings/psychological reaction and the physical act of engaging in sexual activity. Conflating the two, however, is problematic - as it leads to inaccurate and unhelpful commentaries like this one - so we need to be careful with our language about this topic and possibly develop a new term to be more clear.*

 GSA Situations, Now and Future

As reunions between adopted and donor conceived people with their biological relatives explode in number due in large part to the growing use of consumer DNA tests, there will be more people describing the experience of attraction to a genetic relative which they recognize from other experiences as being similar to or indistinguishable from sexual attraction.

Scientific studies are limited, but a limited amount of research and anecdotal stories show this is a real phenomenon. I’ve communicated with some people who have been able to describe the situation and are using the same words used by people describing falling in love with a romantic partner. I wish I had more resources to give them, both for reading and support. Hopefully there will be more developed in the future.

 GSA Support

If you have been involved in a GSA situation, either as the child, parent, or spouse involved, you can connect with a support group. Support groups expand with time as awareness grows, so know that your group may be small now but will almost certainly gain members as more DNA tests are revealing surprise connections between couples, and more adoption and donor conceived reunions are leading to more opportunity for GSA to happen.

If it happens to someone you know, pay attention to what you say in your attempt to be helpful. While well-intentioned, it actually doesn’t help to for someone to hear, “It’s okay, don’t feel that way.” You may believe it to be true and want to provide reassurance. However, everyone is entitled to their emotions and being told not to feel the way you do is called invalidation. Instead, you can offer validation by saying, “I’m so sorry you are going through this shock. I’ve heard of this happening to others before…would you like me to help you try to get in contact with them?”

If you’re a human sexuality researcher, let your colleagues know GSA is an area in which more research is needed. In the past, there were not enough stories or subjects to research, but the exponential growth of both assisted reproductive technology and of consumer DNA testing databases is changing the landscape for GSA research. Your work in this area has the potential to help a lot of struggling individuals and families and the professionals who work with them. 

Most of all, it is important that we show compassion for those who are struggling with the emotional experience after a shocking DNA discovery. If you can’t say anything nice (and supportive), don’t say anything at all.


A heartfelt thanks goes out to Debbie Kennett for reviewing this post and offering some resources and links mentioned herein.

 If you could use someone to talk to about your DNA discovery, know that I offer compassionate, confidential consultations over the phone or video chat**. There is no question too shocking to me, I’ve pretty much heard it all by now. I also am discreet and respectful of your right to privacy, especially about sensitive subjects like GSA.

**Consultations restricted to US residents at this time, but might be available to non-US residents in the future.