In memory of Martin Ritzén (1937–2026)
Emeritus Professor Martin Ritzén, prominent researcher, paediatrician and former Chair of the Nobel Assembly, passed away on 18 July 2026 in Umeå at the age of 89.
Martin Ritzén was born in Dorotea. After completing his schooling in Umeå, he trained as a doctor at Karolinska Institutet and earned a doctorate in cell biology under the world-renowned Professor Torbjörn Caspersson. Martin chose to specialise in hormonal disorders in children and early in his career travelled to Chapel Hill in the United States as a visiting researcher, which became a second home for the family. After returning to Sweden and Stockholm, Martin founded the paediatric endocrinology research laboratory.
Martin’s research into male reproduction received major international recognition. He helped demonstrate that some children who are born with the male sex chromosome Y lack receptors for testosterone, meaning that they appear female. As an expert for the Olympic Committee, he successfully argued that they should be allowed to compete in women’s categories. He was also active in research into adrenal disorders, sexual development and growth. When growth hormone (GH) became more widely available in the mid-1980s, Martin contributed to the formation of a Swedish GH advisory group, paving the way for successful research that today enables even children with rarer diagnoses to be treated with GH. Martin received the Jahre and Andrea Prader prizes, as well as other prestigious honours.
Martin was also deeply engaged internationally, organising many international courses and conferences, teaching colleagues in Nairobi, and serving as chief editor of the international journal Acta Paediatrica.
Martin Ritzén was appointed Professor of Developmental Endocrinology at Karolinska Institutet in 1984. Martin held many positions at Karolinska Institutet, including membership of the Faculty Board from 1977 to 1980 and 1984 to 1990, membership of the Nobel Committee for Physiology or Medicine from 1983 to 1984, membership of the Nobel Assembly from 1984 to 2002, and Chair of the Nobel Assembly in 1999.
Martin Ritzén was a kind, generous and humble person who touched many lives. He will be deeply missed by all friends and colleagues at KI.
Lars Sävendahl, Head of the Division of Paediatric Endocrinology
Kristina Gemzell Danielsson, Head of the Department of Women’s and Children’s Health