Bengt Källén passed away on Wednesday, June 9, 2021. He turned 92 one week earlier. An exceptional scientist and a very special human being.

Listening to him presenting a study he did was enough to quickly be convinced. His talks always were extremely sober: a simple sheet of recycled paper, or at the very least a transparency on an overhead projector, then a few concise, clear sentences, monochrome graphs, and the audience was led towards science, the real thing, towards doubt, criticism, and possible directions when reading the results. To my knowledge, he hardly ever used commercial software. He programmed his own statistical analyses.

The mass of his articles and the number of books he wrote attest to his power of work and the range of what I dare to call his brilliant thinking. Some people think he was an embryologist or a teratologist, others think he was an epidemiologist or a biostatistician. He was all of these at the same time. Others still know him for his research in immunology, which he conducted on (with?) the rats that lived in the basement of the Tornblad Institute, just downstairs. He probably had other scientific skills that I do not know about.

I will quote a few key sentences that are messages he passed on to me:

“The best statistician in the world will not get any results with poor data.”

“Look at a cluster in the eye, and it disappears.”

When people expressed their admiration for him, he replied: “I thrive on flattery”.

Let’s talk about the Lund Group. A group of friends, international if you judge by its composition, which has varied over the years: Lisbeth Knudsen (Denmark), Pierpaolo Mastroiacovo (Italy), the late Eduardo Castilla (Argentina) and his wife Ieda Orioli (Brazil), Osvaldo Mutchinik (Mexico), Maria-Luisa Martinez-Frias (Spain), Paul Lancaster (Australia), John Harris (USA). Others participated in some of the studies, such as my friend Christine Francannet (France), or Guido Cocchi (Italy), or Lorenzo Botto (Italian American).

Many anecdotes can be recalled, such as the decision to study congenital heart disease taken by Bengt with Christine during a swim in Brazil. This was the famous “swim study”. I also often quote a proposal from Bengt at the end of a case-control study concerning hypospadias and their link with in utero progestin exposure in children. Seven of us provided data, which he analysed, which we discussed at length. The association found was borderline significant. He then asked the group a simple question: what do you think? Do progestins taken by a woman during pregnancy increase the risk of hypospadias in her child? In front of our doubtful faces, he proposed a secret ballot, and immediately grabbed a hat, in which we had to write simply yes or no. I recall that there were 7 of us epidemiologists. When the ballot was counted, there were 3 “yes” votes, 3 “no” votes and one “I don’t know” vote. He then explained that he knew who had voted what: those whose day-to-day work consisted of using the case-control protocol answered yes, those with a more clinical background answered “no” and the one who was known to combine the two approaches did not vote. This story is a typical example of the lessons of wisdom I have learned from Bengt.

I would now like to describe the man he was as I got to know him in his family setting. He was indeed so generous that he provided a room in his house for visiting researchers, as much as possible. He welcomed us with his wife Ingegerd, who prepared delicious meals concluded by gourmet desserts whose recipe I often took in my luggage.
These dinners at his home were the occasion to recall the endless anecdotes about our travels around the world linked to the International Clearinghouse annual conferences. Over the years I got to know his taste for English humour: for example,he could laugh out loud at Mr Bean or at “4 Weddings and a Funeral”.

A glance through his library made me leaf through children’s books, which I realised he had written himself, and illustrated for his grandchildren. We had further evidence of his concern for them on a Saturday morning in the early 1990s. The Lund Group often met at weekends because airfares were much cheaper for those who stayed overnight from Saturday to Sunday, and we researchers had extremely limited budgets. That Saturday morning, he got a phone call that made him stop the meeting.He apologised and disappeared for about 30 minutes. When he came back, he explained that his daughter had left the day before, after a stay at their house, forgetting her little girl’s doll. She had asked her father to go and get the doll from his home, put it in a box and post the package urgently. This was also Bengt’s scale of values.

His affection for his family extended of course to his dogs. I saw several of them at Bengt and Ingegerd’s house, not always knowing which one was the house dog and which one was boarding for a few days if one of the children was away. If a dog were ill, Bengt would diagnose it and treat it, including when surgery was necessary.
He was also able to do the necessary renovation work in the house, whether it was plastering or painting, whether it was the one in Lund or the one in Båstad, a seaside resort on the North Sea where he had a summer house.

Can you believe it? He was also a literary critic for the Lund library. He read in at least three languages (Swedish, English and German), and then wrote book reports to help readers make their choices.

So was Bengt Källén, he was a professor of embryology at Lund University. He was my mentor and above all my friend. He will be missed.

Elisabeth Robert












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