Albert Kausch's case, "Ignorance hinders food science advances," (April 14) for using Genetically Modified Organisms (GMOs) , and not labeling them, is based on easing world hunger.

A study done by the Union of Concerned Scientists ("Failure to Yield" www.ucsusa.org/assets/documents) disputes this. After over 20 years of use, GMO crop yields are not greater than yields from conventional crops.

And why should they be? GMO crops are designed to be immune to specific herbicides, or to produce pesticides (such as BT) within the plant tissue. I have used BT for years to kill caterpillars but I don't want to eat it. Sprayed on plants sunlight degrades it within days; within plant tissue it keeps on working.

Some countries have restricted or banned GMO crops, or required labeling of foods containing GMO ingredients. In our free market capitalist system products are accepted or rejected by buyers making free choices, but in order for this system to work effectively there has to be transparency.

Foods containing GMO ingredients should be so labeled and compete in the marketplace with other products. Let the buyers decide if there is any benefit to them from GMOs, or if they do not wish to be guinea pigs in this long-term experiment.