In Podpeskar v. Dannon Company, Inc.,(*), the plaintiff sought to advance a class-action suit against the company because of the word "natural" - and the plaintiff contended that because some of the milk came from cows fed GMO feed it could not be natural. GMO is an acronym for genetically modified organism, essentially a way to optimize a trait using transgenic science, a popular tool that came after previous genetic engineering techniques like mutagenesis, from which many foods certified "organic" were created.
Dannon asked to dismiss the case because U.S. Food and Drug Administration (FDA) regulations don't really define term “natural” beyond being 'not' synthetic. For example, if you take a gene from one potato that is in South America and is resistant to blight that is in England and put it in the same potato in England, it is not synthetic. The court went a step beyond that, noting for the plaintiff that they did not argue that the milk, or any ingredient, in the yogurt was unnatural, which would be a scientific debate, but instead claimed that if the cows producing the milk used to make yogurt ate genetically modified feed their resulting milk and the yogurt made from it was somehow not natural.
It's a marketing argument, the kind of thing Organic Consumers Association pays its trade groups like US Right To Know to claim, but it isn't a scientific or legal predicate.
The court went further, chastising the plaintiff for throwing around facts and statistics about how prevalent GMOs in feed were without having much point. But the real clincher for the court was the plaintiff invoking claims about GMOs "based on her own feelings ... and on a variety of surveys" on consumers' opinions about GMOs.
They would have lost the case anyway, cattle feed is not an ingredient of yogurt, but dismissing it because surveys are not science is going to warm the hearts of evidence-based people everywhere.
(*) No. 16-cv-8478, 2017 U.S. Dist. LEXIS 198948 (S.D.N.Y. Dec. 3, 2017