As a researcher of twins and a consultant for Guinness World Records (GWR), I have encountered many unexpected twin-related events. One of the most amazing occurrences concerns twins born in different countries. A news article revealed that on July 1, 2012, Donna Keenan, a resident of Northumberland, in England, delivered her firstborn twin (a son named Dylan) in her living room, following early labor. However, Dylan’s twin sister was not ready to be born. Donna was immediately transferred to Borders General Hospital in Melrose, Scotland, where she delivered her second twin (a daughter named Hannah) approximately 90 minutes later. After an exhaustive search, I did not detect any other transnational twin pairs and concluded that Dylan and Hannah were the first of a kind. I submitted this “record” to GWR. I was wrong.

Truly the First Transnational Twin Pair

Heidi Gannon and her twin sister Jo Baines are residents of Welshpool, Wales. When Heidi’s son William looked through the GWR 2016, he was puzzled to see the reference to Dylan and Hannah, since it contradicted the story his mother had always told him—that on Sept. 23, 1976, Heidi and her twin sister had been born in different countries, namely Wales and England, respectively. Heidi confirmed the story for her son and placed a photograph of the GWR page on Facebook with the headline “Sorry, Guinness Book of Records, but You're Wrong.” The news spread once Heidi’s friend, an editor of a local online newspaper, decided to publish the story. Eventually, GWR saw the item and contacted me, and a correction with this new information was verified. No other such twin pair has since come forth to challenge that record. I was surprised I had not discovered it initially, but I was pleased that it was updated. (Apparently, the word combination and/or word order I used in my internet searches were not optimal.) Both twins expressed sympathy for Dylan and Hannah, whose “record” was taken away.

Heidi and Jo had been born apart because of unexpected events at Heidi’s delivery. Physicians had not suspected that their mother, Carol, was pregnant with twins—it was only when Heidi was born 10 days ahead of her due date at the local Welshpool hospital that a second baby was detected. It became mandatory to deliver the second twin at a better-equipped hospital because of her transverse presentation. Jo was born 18 miles away in Shrewsbury, England, about one hour and 45 minutes later, at the Royal Shrewsbury Hospital. Both twins were generally healthy, with birth weights of 5 pounds, 4 ounces (Heidi), and 6 pounds, 8 ounces (Jo). Jo received oxygen and while Carol was informed that Jo might show some cognitive difficulties, Jo has proven the doctors wrong.

Carol remained in the hospital for the required 10 days following delivery. During that time, a nurse entered her room and asked, “Do you realize you are going to be famous? I’m going to phone the newspapers.” Many interviews, articles, and appearances followed.

Over the years, the twins’ story continued to attract attention. For example, on their 10th birthday, a local newspaper included a photograph showing the twins standing on opposite sides of the Powys-Shropshire border—Heidi in Wales and Jo in England.

Meeting the Twins

I asked GWR to put me in touch with the twins. I learned that they were somewhat uncertain as to their twin type. Heidi and Jo have very similar faces, but their height difference of 3 to 4 inches and some health-related differences have caused them to question their twin type, especially after puberty when their disparities became more pronounced. I arranged for the twins to have DNA testing, which eventually showed what their mother had always believed—that her twin daughters were identical twins. Carol had been told that her girls were identical based on their having just one placenta, but that fact does not definitively define identical twins because the separate placentas of fraternal twins are fused nearly half of the time. Like approximately 25% of identical twins, Heidi is left-handed, while Jo is right-handed. In addition, their hair whorls show a reversed direction and Heidi has a double crown.

I finally visited the twins and their mother in Wales, in June 2023, after my invited lecture series at the University of Aberystwyth, also in Wales. During and after dinner, Heidi and Jo discussed their twinship, family life, interests, and education. Both twins were happy to know their twin type with certainty and were pleased that they are identical. Jo had completed college, and Heidi studied nursing for two years but did not complete the training. Jo was married, while Heidi was divorced but in a significant relationship. Both twins had each given birth to two children. Jo has worked in education, while Heidi left nursing, worked at several different jobs, then obtained national vocational qualification (NVQ) for child care. I was intrigued to learn that both twins’ faces can open each other’s cellphones—Heidi has a Samsung and Jo has an Apple iPhone. Several years ago, I performed a similar experiment with MZ male twin students and discovered that one twin could unlock his co-twin’s laptop computer with his eyes.

Citizenship

Heidi and Jo are both citizens of the United Kingdom (U.K.) despite their birth in Wales and England. Jo enjoys the same rights and privileges as her Wales-born twin sister and they hold the same passport—because the U.K. is structured as it is, citizenship differences do not exist among people born in Wales, England, Scotland, or Northern Ireland. All four nations have the same age, residency, and registration requirements for voting, and Jo could run for elected office in Wales if she chose to.

The situation of these twins offers a sharp contrast to the twins I described in my 2023 book, Gay Fathers, Twin Sons: The Citizenship Case That Captured the World. Andrew Banks, an American citizen, and Elad Dvash, an Israeli citizen, met in Tel Aviv in 2008 and married in Canada in 2010. They had twin sons with the use of egg donation and surrogacy in 2016 and according to Canadian documents, both fathers were recognized as the legal parents of both children. However, when they decided to relocate to Los Angeles, California, and visited the U.S. Consulate in Toronto to obtain passports for their infant children, their troubles began. They had to cope with cruel and invasive questioning by government officials over who gave birth to the children and if the twins were biologically related. It turned out that one of the two best-quality embryos had been created with Andrew’s sperm (Aiden) and the other by Elad’s (Ethan). Ultimately, only Aiden received a U.S. passport, whereas Ethan was given a six-month tourist visa since he lacked a biological connection to an American citizen. This decision was a serious misapplication of the law by the consular officer, as I explain in my book.

Fortunately, both parents had the courage and determination to fight on behalf of their son, Ethan, assisted by attorneys from Immigration Equality and the Sullivan and Cromwell law firm. In 2020, their lawsuit against the U.S. State Department and Secretary of State settled favorably, allowing Ethan to become a U.S. citizen. It seems unimaginable that the twins born in different countries (Dylan and Hannah; and Heidi and Jo) did not differ in citizenship status, whereas Aiden and Ethan who were born in the same country, only four minutes apart, were citizens of different countries until they turned 4 years of age. Andrew and Elad’s efforts on Ethan’s behalf were rewarded, both for their son, for their family, and for families like theirs. These parents eased the way for other transnational same-sex couples whose children are delivered abroad—policy changes were put into place as regulations were revised.

I wish to thank the twins and their mother for sharing the life history events surrounding this important topic. A more detailed version of this post will appear in a forthcoming issue of the journal TWIN RESEARCH AND HUMAN GENETICS.