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I HAVE always been fascinated by people’s cultural relationship with plants. You might assume understanding this is all about voyaging up the Amazon river to learn how indigenous peoples use traditional medicines, but, to me, the most interesting cultural beliefs lie much closer to home. Nowhere is this more the case than when it comes to the contentious issue of genetically modified crops. Yet it might surprise you to know that my concern is exclusively cultural, not scientific.

One of the most intriguing things about culture is that it is such an intrinsic part of how we see the world. It can seem like culture is something only other people have, as within any given culture, its unique biases and preconceptions are largely invisible to those who share them. So it is unsurprising that many people with a cultural aversion to genetic modification are unaware that this is what it is. Many may be convinced that these are valid scientific concerns, reflecting the evidence. To illustrate that this an illusion, all you have to do is look at a few examples.

With so many everyday crops now developed using GM techniques, many argue that choosing organic is the only way to avoid the practice in some countries. On this point, they would be right, but here is where the argument gets tricky. I bought some lovely Star Ruby grapefruit at an organic store the other day. Some may consider these to be perfectly natural, unless, of course, you know about their actual history.

Star Ruby grapefruits are based on a genetic mutation generated by exposing plant material to atomic radiation. Known as radiation mutagenesis, this is a common breeding technique first developed in the 20th century that aimed to create all sorts of novel crop traits, using everything from cobalt-60 released in bursts from underground concrete bunkers in fields to simply strapping seeds to the insides of hospital X-ray machines. The potentially hundreds of mutations created were entirely random and unpredictable, and we have been able to identify only some of them. Everything from a cultivar of mint used to make menthol to a barley variety used to make beer were created through this technique and it is still in active use today.

By comparison, modern GM techniques that identify single genes, potentially just turning one on or off, are far more precise and are run through a battery of tests. So if your concern about genetically modified organisms is based on unknown consequences of tinkering with the genome, then the range of organic crops created via radiation mutagenesis, with their mysterious catalogue of random, untested mutations, would logically be far, far more worrying. Perhaps surprisingly, there seems to be no such fear.

“The transfer of genes happens all the time in nature. So if you are against GM crops, you are against sweet potatoes”

Yet as in all cultures, the concern about GM crops isn’t monolithic. You may be perfectly comfortable with the idea of inducing genetic mutations – after all, these occur all the time in nature. It might just be the extent to which we can transfer genes from one species to another that troubles you. The seemingly unprecedented ability to make changes on this scale can understandably make transgenic crops feel culturally challenging.

However, let’s consider the case of the sweet potato. All cultivars of this crop contain bacterial genes that were transferred into them thousands of years ago. In fact, the insertion of genes between species actually happens all the time in nature through a process known as horizontal gene transfer. So if you are against GM crops, you are against sweet potatoes. Depending on how far you want to take the argument, you might even be concerned about your own body, which contains 100,000 pieces of viral DNA inserted in our distant past, making up to 8 per cent of the human genome.

You might say that these changes to genes took place so long ago that millennia of testing has had the chance to identify any long-term side effects. Then again, you might find it surprising to learn that millennia of use is by no means evidence of safety – take comfrey, for example, an ancient crop that has only recently been shown to be unsafe to consume in large quantities. The problem with the precautionary principle – the idea that caution should always win out – isn’t just that following it to its logical conclusion means no innovation can ever truly be justified, but that it seems to be applied in a highly selective way to concepts to which we already have identified a cultural aversion.

Now, as someone interested in cultural beliefs about food, I don’t think I can dismiss the ideological aversion to genetically modified organisms anymore than I would the cultural taboos some people have about eating pork, beef, meat in general or even root vegetables. Yet it is important to clarify that this is what they are: cultural, not scientific.