Genetic Determinism: Fact or Fiction?


Fifteen centuries ago, Euripides wrote that “Fate is stronger than anything.” We believe in a different kind of “fate” today. It’s not based on impersonal forces, but science: genetic determinism.

“Upset with your teenager’s bad grades? A new study says it might not be their fault. Their genes are to blame!” It seems that every week a new study comes out finding correlations between genes and all sorts of physical traits, such as height, behaviors like violence, and diseases such as heart disease and ADHD.

This steady stream of genetic studies has led some to believe we are predisposed to certain genetic conditions, physical traits and behaviors and there is not much we can do about it. In other words, our genes determine who and how we are. This belief is known as genetic determinism.

You might think that genes have an “all or nothing” effect. That is, if you have the gene, you will get the trait or disease. Some genes do behave this way, such as the gene for Huntington’s Disease. Because this is the simplest way of understanding how genes work, it’s often how they are explained in high school biology classes. In reality, it is much more complicated than this.

Multiple genes are usually involved in determining a single trait or disease, making it hard to sort out which gene does what. Take for example, eye color. In order to get your particular shade of brown, blue, or green eyes, several genes are involved. Genes also interact with each other, causing the effects of the other genes to be enhanced or suppressed. Scientists are still figuring out these complex interactions.

We also know that genes can be influenced by the environment, even at the level of the cell. Everything from medications to chemicals, temperature, and light, affects how our genes are expressed, that is, “turned on” or “off.”

Think about behavior. We know that it is also influenced by our personal experiences, including the kind of home we grew up in and how we are treated by others. And from a Christian perspective, there is much more that we would want to say about why we do the things that we do. Our bad behavior isn’t caused by our genes. Dare I mention “sin”?

We also know that while some behaviors and diseases do have a genetic component, the part the play is very small. For example, obesity has more to do with poor diet and lack of exercise than with your genes.

Unfortunately, the myth of genetic determinism has been perpetuated in the marketplace. Some companies sell genetic tests guaranteed to unlock the secrets of “your genetic future,” as if that’s all you need to know.

As Christians we know that God is the author of all creation, including our genes. We also know that this creation is very complex. Just as Fate was not the whole story for the world of ancient Greece, neither is our story told in our genes. The news headlines are wrong; genetic determinism is more fiction than fact.


Everyday Bioethics Audio Commentary Album Art