Types of Cloning: Three Different Things, One Confusing Word
Gene cloning, therapeutic cloning, and reproductive cloning all share a name and a basic idea. They are otherwise very different in purpose, scale, and ethics. Here is the side-by-side comparison.
The word “cloning” gets used in headlines, films, and policy debates to mean wildly different things. Some are routine laboratory work that has been part of biology for decades. Others remain hypothetical and largely prohibited. The most reliable way to think about cloning is to keep three categories firmly separate.
1. Gene (molecular) cloning
What it is. Copying a specific stretch of DNA — typically a single gene — by inserting it into a host cell, usually a bacterium, that replicates it for further study or use. Sometimes called recombinant DNA work.
What it does. Gene cloning underlies a huge amount of modern biology. It is how researchers produce insulin, study how individual genes function, develop diagnostics, and engineer vaccines. Without it, much of contemporary medicine simply would not exist.
What it does not do. Gene cloning does not produce a copy of an organism. It produces copies of a piece of DNA. The bacterium carrying the cloned gene is still a bacterium.
Status. Routine. Performed in thousands of laboratories around the world under standard biosafety rules.
2. Therapeutic cloning
What it is. A research technique in which somatic cell nuclear transfer (SCNT) is used to produce early-stage cells that can be studied in the laboratory — most often to derive stem cells that share the DNA of a specific donor.
What it does. Therapeutic cloning is investigated as a way to learn about disease, develop potential cell-based therapies, and study how cells differentiate. The goal is cellular research, not reproduction.
What it does not do. Therapeutic cloning does not produce a baby. The cells involved are not implanted in a uterus. In most jurisdictions where it is allowed, embryos created by SCNT must be destroyed within early developmental limits and cannot be used reproductively.
Status. Heavily regulated and treated differently in different countries. Some permit it under tight oversight, others restrict it more narrowly, and others prohibit it.
3. Reproductive cloning
What it is. The use of SCNT or related techniques to produce a living organism that is genetically very similar to an existing one. Dolly the sheep (1996) is the most famous example, and many other mammals have been cloned since.
What it does. In animals, reproductive cloning is used for research and, less commonly, in selective livestock breeding. In humans, it has not been done.
What it does not do. Reproductive cloning does not produce a perfect copy of a person. Even in animals, cloned individuals differ from the donor in development, environment, and behaviour. Identical DNA is not identical life.
Status. Reproductive cloning of humans is broadly prohibited around the world and is treated by leading scientific and medical bodies as unsafe and ethically unacceptable in current circumstances.
The shortest version
- Gene cloning copies a piece of DNA. Routine.
- Therapeutic cloning copies a cell’s nucleus for research. Tightly regulated.
- Reproductive cloning copies an organism. Done in some animals, not in humans, and broadly prohibited.
Why the distinction matters
Public conversations about cloning often slide between these three meanings without warning, which makes intelligent discussion almost impossible. A policy that restricts reproductive cloning is not the same as a policy that restricts molecular cloning, and a debate about embryonic stem cells is not the same as a debate about making babies.
If you are reading a news story or a policy document about cloning, the first thing to ask is which of these three categories it is talking about. The answer almost always changes the conclusion.