Governments and consumers around the world are rightly cautious about the introduction of genetically modified crops that are promoted by the scientists and corporations that develop them as the answer to food safety in an increasingly populous world.

People can be notoriously conservative about what they put in their mouths even in the face of expert assurances that innovations such as GM foods are perfectly safe.

This tension has been nowhere more apparent than in a heated debate over the development of "golden rice", touted at the turn of the century as a modified crop that could save the lives of one million children a year.

In countries, particularly in Asia, where rice is a staple, "golden rice" modified with a maize gene to add beta-carotene and vitamin A, promises to save the sight of children from poor families who might otherwise go blind and to protect expectant mothers.

Over almost two decades studies and trials have been carried out in a range of target countries in the face of skepticism from food safety and development lobbies and the caution of regulators. Only now is the government of Bangladesh, a major rice producer and consumer with high levels of vitamin A deficiency, preparing to take a decision in November on releasing the first GM variety.

Environmental groups such as Greenpeace have been at the forefront of the campaign against the modified rice, questioning whether it is safe or will live up to its promise.

The Grain charity, which supports small farmers, says that the push to introduce the GM crop amounts to a corporate ploy to control agriculture at the expense of traditional small-scale producers. Such resistance has fueled protests by small farmers in Asia who see their livelihoods threatened by the introduction of GM crops.

In the pro-GM camp, a group of scientists including Nobel laureates have condemned Greenpeace for a campaign allegedly based on emotion and dogma and declared, in an open letter in 2016, that "there has never been a single confirmed case of a negative health outcome for humans or animals from their (GM crop) consumption".

The modified rice has won international plaudits as a major humanitarian breakthrough and in 2013 even earned a personal blessing from Pope Francis, despite concerns shared by the Catholic Church that GM technology primarily benefits big business and not the poor.

The latest salvo from the pro-GM lobby comes from US science writer Ed Regis in his book Golden Rice: The Imperiled Birth of a GMO Superfood in which he states: "In Bangladesh, China, India and elsewhere in Asia, many children subsist on a few bowls of rice a day and almost nothing else. For them, a daily supply of Golden Rice could now bring the gift of life and sight."

Consumers in those countries, it appears, are not so easily convinced. Nature, the UK science journal, published a survey last year that found just more than one in ten of Chinese respondents had a positive view of GM food. More than 45 percent were opposed to it.

That caution has been reflected in official policy which has largely restricted the commercial use of GM varieties to non-food farming while the wider introduction of modified food crops is considered.

An element of caution appears justified in the face of the pro-GM lobby's haste to win approval. In 2012, Chinese authorities dismissed three officials for breaching laws and ethical regulations by testing genetically modified rice on children without informing their parents and teachers.

In the face of contradictory viewpoints on GM, governments and consumers are obliged to look at the evidence. In the case of "golden rice", there is no evidence it is harmful but doubts have been raised over how reliable it is at delivering the promised benefits. Some argue vitamin A supplements, while expensive, would save as many lives without forcing a revolution in rice production.

Modern science has improved and lengthened countless lives but sometimes advances can have unforeseen and unintended consequences.

Consumers were once assured that it was perfectly safe to feed cattle with processed meat and bone meal. That was before the emergence of BSE, the so-called mad cow disease that spread from the feed to threaten both cattle and people.

At around the time "golden rice" was first being developed, Chinese authorities approved the introduction of a GM cotton variety that would poison its main pest, the bollworm.

It allowed farmers to successfully grow their crop with the use of less pesticide. A ten-year study, however, revealed a boom in the number of other pests that had previously had only a minor impact. Science, it seemed, had removed one problem only to replace it with another.

Scientists will often see official and consumer caution as annoying and unnecessary restraints on advances in the production of food and other staples.

But they also have to recognize that they do not always get it right.

Harvey Morris is a senior media consultant for China Daily UK