Jack Nunn was 21, his girlfriend a year younger, when she died suddenly while the couple were in England.

Nunn had been studying literature, but that shocking tragedy in 2007 launched him on 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 Ph.D. in public health genomics, and more immediately led his mother, Barbara Nunn, to a reckoning with both the family she had grown up with and a large cohort. of up to 1,000 new half-siblings. .

“I feel that the experience of discovering unexpected close family members has brought surprise, but more joy and interest to my life than I could have imagined,” she says.

The astonishing turn of events for mother and son began when an autopsy on Jack Nunn’s girlfriend showed that she had died of sudden adult death syndrome, which likely had a genetic component.

Jack Nunn began working with health charities and wondered how the public could be a part of questions about research, policy, and funding priorities.

She moved to Australia in 2014 and went into public health at La Trobe University. He says he knew “instantly” that he wanted to study genomics research from that personal and formative experience with his girlfriend. As he embarked on his doctorate, he decided that he needed more personal experience.

“I thought, well, let’s do a DNA test on my mom,” he says.

“So I encouraged her to share her DNA on a website. And through that, someone contacted my mom and said, ‘I think you might be my half-aunt’… it became clear that, in fact, my mom was most likely donor conceived. of sperm.

“This would have been in 1949, in London.”

Nunn’s social grandfather, a World War II veteran, had a condition that required him to undergo multiple X-rays, a possible source of infertility. So his grandparents visited a clinic, at a time when male fertility issues were just beginning to be understood.

That clinic was owned by an obstetrician, Dr. Mary Barton. It was eventually revealed that her husband, biologist Bertold Wiesner, was the “anonymous” sperm donor she used in procedures that resulted in up to 600 inseminations.

This was long before regulations began to catch up on sperm donations. But DNA matching via ancestry websites means more people are discovering not only that their social parents or grandparents aren’t their biological relatives, but that they have far more genetic relatives than they might have imagined.

“I suddenly found out that I was part of one of the largest known single ancestor cohorts on planet Earth, which was pretty amazing,” says Jack Nunn.

“So potentially I have 1,000 half-aunts and uncles out there, and a lot of half-cousins. It’s exciting, it’s interesting.

“And there are also many potential organ donors.”

Wikipedia, he notes, lists Genghis Khan as the man who has fathered the most children in the history of the world. In second place is Wiesner.

Wiesner, by extrapolating data from genetic testing of some of those born at the clinic, is estimated to have had as many as 1,000 children (some estimates put it as low as 600).

‘Shock and disbelief’

Barbara Nunn describes herself as “a passionate amateur family historian.”

When the family gave her a DNA test for her 65th birthday, they were shocked to discover that she was 50% Ashkenazi Jewish. She guessed that she came from her Greek grandfather and she uploaded the results to GEDmatch, a genealogy 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 was wondering if I knew that she (and I) had another half-sister in Canada. the United Kingdom. He asked me if my father had been a sperm donor,” she says.

“Naturally I was in shock and even a little upset, so I replied that I was sure that had not been the case, as my father had been in poor health after the Second World War.”

He did another test, got the same results, and began to discover more sibling donors. She says she felt “shock and disbelief.”

“It’s been a challenge to share this news with family members who are now not biologically related, but I’ve been very lucky because, unlike some who find out they’re donor-conceived, they have assured me that their love continues,” she says. .

He found more half-siblings and learned about Wiesner and Barton.

Now he speaks 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, nor in most countries. States and territories have limits on the number of families sperm donors can create, usually five or 10.

But there has been an increase in informal sperm donation, using social networking sites like Facebook. The recipients, mostly single women and same-sex couples, are forgoing the regulated clinical industry in favor of finding a donor online.

In addition to the risks inherent in leaving the formal system, there is the potential trauma caused to donor-conceived individuals. The main national body, Donor Conceived Australia, says it is “distressing” for people to find out they have a large number of siblings, a situation that can occur within the formal system, but more easily outside of it.

For Barbara Nunn, the most important issue is the right to know.

“DNA does not allow readings. The truth must be shared,” she says.

“Not disclosing true paternity can and does have devastating medical or psychological consequences for some.

“Fifty percent of DNA comes from a biological parent and all donor-conceived children have the human right to access half of their inherited medical history. This not only affects them, but the children or grandchildren they may have.”

In his PhD, Jack Nunn analyzed various communities. One with a rare disease, another multi-generational 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. They are now exploring the possibility of establishing a family biobank, so everyone can participate in shaping future research on this intriguing cohort.

Nunn established a feedback loop between his personal life and his professional work, working on standardized ways to create transparency in research, ensuring democratic access and informed consent on how DNA data is used and shared.

“We need better data to help us all make informed decisions, so we can make decisions that align with our values.

“It’s a big part of a people’s identity…their ancestry,” says Nunn.

“It has been democratized and opened, now, [to explore] things like variations in the genome, which may or may not increase or decrease the risks of certain diseases, or even well-being,” he says.

Nunn says that everyone reacts differently to learning about their genetic history, but he personally was looking forward to a planned meeting with relatives in London.

“What was very shocking to me was seeing the same body language, gestures and sense of humor,” he says.

“There were people here who had the same sense of humor as me, which, I have to admit, is really dark. I made some kind of cheeky joke. And everyone loved it, and went even further.

“There is one woman in particular… the first time I met her, I was quite shocked. Because she was a lot like my mother… the way she talks, the way she moves.”

Nunn says those interactions changed his ideas about the old nature vs. nurture debate, about what it meant to have a community of shared ancestry, and about how to engage that community in his work.

“We have this new frontier in understanding ourselves,” he says.