Strange but ultimately positive genetic discovery reveals up to 1,000 relatives linked to prolific sperm donor
Jack Nunn was 21, his girlfriend a year younger, when she died suddenly while the pair were in England.
Nunn had been studying literature, but that shocking tragedy in 2007 threw him on to a new path that would end in a strange but unexpectedly positive discovery – that his grandfather was one of the world’s most prolific sperm donors, leaving him with thousands of close relatives.
The revelation became part of Nunn’s study for a PhD in public health genomics, and more immediately brought his mother, Barbara Nunn, into a reckoning both with the family she had grown up with, and a vast cohort of up to 1,000 new half-siblings.
“I have felt that the experience of discovering unexpected close family has brought shock, but more joy and interest into my life than I could have imagined,” she says.
The astounding turn of events for mother and son began when the autopsy on Jack Nunn’s girlfriend showed that she had died from sudden adult death syndrome, which was likely to have had a genetic component.
Jack Nunn began working with health charities, and wondering how the public could be part of questions around research, policy and funding priorities.
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He moved to Australia in 2014, and into public health at La Trobe University. He says he “instantly” knew he wanted to study genomic research thanks to that formative, personal experience with his girlfriend. When he embarked on his PhD, he decided some more personal experience was needed.
“I thought, well, let’s get my mum a DNA test,” he says.
“Then I encouraged her to share her DNA on a website. And through that, someone got in touch with my mum and said: ‘I think you might be my halfaunt’… it became apparent that, in fact what was most likely, was that my mum was conceived by sperm donor.
“This would have been in 1949, in London.”
Nunn’s social grandfather, a second world war veteran, had a condition that meant he had to have multiple X-rays, a possible source of infertility. So his grandparents visited a clinic – at a time when male fertility issues were only just beginning to be understood.
That clinic belonged to an obstetrician, Dr Mary Barton. Her husband, biologist Bertold Wiesner, was eventually revealed to be the “anonymous” sperm donor she used in procedures that resulted in up to 600 inseminations.
This was long before regulations started to catch up with sperm donations. But DNA matching through ancestry websites means more people are finding out not only that their social parents or grandparents are not their biological relatives, but that they have far more genetic relatives than they could ever have imagined.
“I suddenly discovered that I was part of one of the largest known single ancestor cohorts on planet Earth, which was quite surprising,” Jack Nunn says.
“So, potentially, I’ve got 1,000 halfaunts and uncles out there, and a lot of half-cousins. It’s exciting, it’s interesting.
“And it’s a lot of potential organ donors as well.”
Wikipedia, he points out, lists Genghis Khan as the man who has fathered the most children in the history of the world. Coming in second is Wiesner.
Wiesner is estimated – by extrapolating genetic testing data from some of those born at the clinic – to have fathered up to 1,000 children (some estimates put it at a mere 600).
‘Shock and disbelief’
Barbara Nunn describes herself as “a keen amateur family historian”.
When the family gave her the DNA test for her 65th birthday, she was surprised to find she was about 50% Ashkenazi Jewish. She assumed that came from her Greek grandfather, and uploaded the results to GEDmatch, a genealogical site similar to Ancestry.com.
“Almost exactly one year later I received an email from a man in Toronto to say that DNA results had shown that his mother in Canada was my half-sister and asking if I knew that she (and I) had yet another half-sister in the UK. He asked if my father had been a sperm donor,” she says.
“Naturally I was in shock and even a little annoyed so replied to say that I was certain that had not been the case, as my father had been in poor health after world war two.”
She took another test, and got the same results, and started discovering more donor siblings. She says she felt “shock and disbelief”.
“It has been challenging to share this news with family who are not now at all biologically related but I have been so fortunate in that, unlike some who find they are donor-conceived, I have been reassured of their continuing love,” she says.
She found more half-siblings, and found out about Wiesner and Barton.
Now she talks and meets regularly with more than 50 people who share Wiesner as a biological father.
What Wiesner did would not be legally allowed now in Australia, or in most countries. States and territories have caps on the number of families that sperm donors are allowed to create – usually five or 10.
But there has been an increase in informal sperm donation, using social media sites such as Facebook. Recipients, mostly single women and samesex couples, are forgoing the regulated clinical industry in favour of finding a donor online.
On top of the risks inherent in going outside the formal system is the potential trauma caused to donorconceived people. The national peak body, Donor Conceived Australia, says it’s “distressing” for people to find out they have huge numbers of siblings – a situation that can happen within the formal system, but more easily outside it.
For Barbara Nunn, the most important issue is the right to know.
“DNA doesn’t permit lies. The truth must be shared,” she says.
“Not revealing true parentage can and does have devastating medical or psychological consequences for some.
“Fifty per cent of DNA is from a biological father and all donor-conceived children have a human right to access half of their inherited medical history. This does not only affect them but any children or grandchildren they may have.”
A community with shared ancestry
In his PhD, Jack Nunn looked at several communities. One with a rare disease, another multigenerational study, another with a remote Aboriginal community.
And he looked at his own donor family.
He included his half-aunts and uncles in co-designing that part of his published PhD. Now they are exploring the possibility of setting up a family biobank, so they can all be involved in shaping future research on this intriguing cohort.
Nunn set up a feedback loop between his personal life and his professional work, and worked on standardised ways of building transparency into research, of ensuring democratic access and informed consent about how DNA data is used and shared.
“We need better data to help all of us make informed decisions, so we can make decisions which align with our values.
“It’s a huge part of people’s identity … their ancestry,” Nunn says.
“It’s been democratised and opened up, now, [to explore] things like the variations in the genome, which may or may not increase or decrease risks of certain diseases, or even wellbeing,” he says.
Nunn says everyone reacts differently to finding out their genetic history, but he personally looked forward to a planned meeting with his relatives in London.
“What for me was very shocking, was seeing the same body language, the mannerisms and the sense of humour,” he says.
“Here were people who had the same sense of humour as me, which I have to admit, is really dark. I sort of made a bit of an edgy joke. And everyone loved it, and went even further.
“There’s one woman in particular … the first time I met her, I got quite a shock. Because she looked very similar to my mum … the way she speaks, how she moves.”
Nunn says those interactions flipped his ideas about the age-old debate about nature versus nurture, about what it meant to have a community with shared ancestry, and about how to involve that community in his work.
“We’ve got this new frontier to understand ourselves,” he says.
Potentially, I’ve got 1,000 half-aunts and uncles out there, and a lot of half-cousins. It’s exciting, it’s interesting