Conjoined twins are identical twins who are physically connected to each other at birth. This condition occurs when a fertilized egg only partially separates during early development in the womb.
Depending on how and where the separation stops, conjoined twins may share organs, limbs, or other parts of the body. Medically, the term conjoined twins is now universally used because it is descriptive, neutral, and focused on biology rather than geography or culture.
However, for much of modern history, especially in Western societies, conjoined twins were commonly referred to as “Siamese twins,” a phrase that carries a specific historical origin.
The Lives of Chang and Eng Bunker
The term “Siamese twins” originates from the lives of Chang and Eng Bunker, the most famous pair of conjoined twins in history. They were born in 1811 in Siam, the country now known as Thailand.
Chang and Eng were joined at the chest by a band of cartilage and shared a liver, though they had separate hearts and vital systems. Despite their physical connection, they were remarkably healthy and capable of living long, active lives.
In the early nineteenth century, Chang and Eng were brought to Europe and later the United States, where they were exhibited to the public. At the time, such exhibitions were common and often framed as scientific curiosities or public spectacles.
Because Chang and Eng were from Siam and were the first widely known conjoined twins to be documented and publicized on an international scale, the public began associating their condition directly with their place of origin.
How the Name Became a Generic Label
As Chang and Eng gained global fame, newspapers, medical journals, and popular literature referred to them as the “Siamese twins.”
Over time, this label began to lose its connection to the two individuals and instead became a generic term for all conjoined twins, regardless of where they were born.
This linguistic shift reflects a common pattern in language, where a highly visible or influential example becomes the name for an entire category.
The spread of the term was reinforced by the limited medical understanding of the time. Conjoined twinning was rare and poorly understood, and Chang and Eng remained the most prominent example for decades.
As a result, their story shaped public perception to such an extent that their nationality became inseparable from the condition in the popular imagination.
Cultural Context and Western Perspectives
The use of the term “Siamese twins” also reflects the cultural and colonial mindset of the nineteenth century. Western audiences often viewed people from Asia, Africa, and other non-European regions through an exoticizing lens.
Labeling conjoined twins as “Siamese” subtly reinforced the idea that such physical differences were foreign or unusual in a way that set them apart from Western norms.
This framing ignored the biological reality that conjoined twins have been born in every part of the world throughout history.
Historical records and archaeological evidence suggest that conjoined twins existed long before Chang and Eng and across many different cultures. However, because Western media and science dominated global discourse at the time, the Siam-based label persisted.
The Shift Toward Medical Accuracy
As medicine advanced in the twentieth century, understanding of embryology and human development improved significantly.
Scientists learned that conjoined twinning results from incomplete division of a single embryo and has no connection to ethnicity, nationality, or geography.
With this knowledge came a shift in terminology. The term conjoined twins began to replace “Siamese twins” in medical literature because it accurately describes the condition without unnecessary cultural associations.
This change also reflected broader efforts within medicine and academia to use language that is precise and respectful.
As societies became more aware of how terminology can shape attitudes and reinforce stereotypes, the old term began to be seen as outdated and potentially misleading.
Why The Term Is Now Considered Inappropriate
Today, “Siamese twins” is generally regarded as an obsolete and sometimes insensitive term. It incorrectly implies a geographic origin and reduces a complex medical condition to a historical curiosity.
For people who are conjoined twins or have personal connections to them, the term can feel dehumanizing, as it emphasizes spectacle over individuality and medical reality.
Modern usage favors language that centers on the people involved rather than their differences. “Conjoined twins” is descriptive, neutral, and free of cultural bias, making it the preferred term in both professional and everyday contexts.
A Historical Term with Lasting Lessons
The history of the term “Siamese twins” offers insight into how language evolves and how cultural context shapes medical terminology.
While the phrase emerged from the real and remarkable lives of Chang and Eng Bunker, its widespread adoption also reveals how easily a single story can define an entire category of people.
Understanding this history helps explain why the term was used for so long and why it has largely been abandoned today, in favor of language that reflects accuracy, respect, and a deeper understanding of human diversity.
