The Swedish Twin Registry: Scientific contributions to research and medicine

Critical genetic data for research, leading to groundbreaking discoveries and advancing the understanding of nature and nurture. The Swedish twin registry offer profound implications for personalised medicine and public health.


The Swedish Twin Registry (STR) is one of the world’s most comprehensive and influential resources for twin studies. Established in the early 1960s, it has played a pivotal role in advancing our understanding of genetics, heritability, and the interplay between genes and the environment. This case study explores the history, development, and significant contributions of the Swedish Twin Registry to the field of scientific research and medicine.


The Swedish Twin Registry originated from a research initiative led by Professors Rune Cederlöf and Lars Friberg, Swedish geneticist, who recognised the potential of studying twins to unravel the mysteries of human biology and genetics. The registry began with a modest group of participants, but over time, it evolved into one of the largest and most valuable twin databases globally.

Establishment of the Registry (1960s-1970s):

The Swedish Twin Registry officially commenced in the early 1960s with the primary goal of studying Genetic and environmental factors of various traits. Early efforts focused on recruiting and enrolling twin pairs from across Sweden, both identical (monozygotic) and fraternal (dizygotic) same sexed twins until 1998. Detailed health questionnaires, medical examinations were conducted on the twins, creating a rich dataset for research.

Genetic Research Breakthroughs (1980s-2000s):

Throughout the 1980s and 1990s, researchers within the STR made significant contributions to the understanding of genetics. Twin studies conducted at the registry led to groundbreaking findings regarding the heritability of complex traits such as intelligence, personality, and various medical conditions. The registry’s repeated observations allowed researchers to investigate the influence of genetics and environment on health outcomes over time.

Advancements in Twin and Genetic Epidemiology (2000s-present):

The STR continued to expand, collaborating with international research teams to collect data on an even larger scale. Advances in genotyping technology allowed for more precise genetic analysis of twins, enabling the identification of genes associated with various diseases. Twin studies conducted at the STR could play a role in the development of personalised medicine and targeted treatments.

Contributions to Public Health

Data from the Swedish Twin Registry has had a significant impact on public health in Sweden and globally. Findings from twin research have informed healthcare strategies, disease prevention programs, and family counselling services. The registry’s data has been instrumental in understanding the hereditary nature of diseases like cancer, cardiovascular conditions, and mental health disorders.


The Swedish Twin Registry is a testament to the power of large-scale repeated observations of the same variables over long periods of time and international collaboration in advancing scientific knowledge. Over its decades-long history, the registry has provided invaluable insights into genetics, heritability, and the complex interplay between genes and the environment. It has not only contributed to the academic understanding of these concepts but has also had impact on public health and medical practice. As the registry continues to grow and evolve, its contributions to science and medicine are likely to remain at the forefront of twin research for years to come.

Related cases