Food packaging, labeling and marketing laws vary greatly by geography and even within geographies.
In the United States, all food is labeled in accordance with Food and Drug Administration policy, which is the same for foods derived from biotechnology as it is for conventional foods. When a food product derived from biotechnology differs in composition, nutritional value or end use, that difference must be noted on the label, just as it is with other foods (e.g., margarine versus low-fat margarine). Most foods from biotech crops are not different by FDA standards and therefore not required to be labeled in the United States.
The labeling question continues to be debated here in the States, but the important thing to know is that we believe information for consumers is a good thing. That is why we sponsor this forum where consumers can ask their questions directly of us―independent scientists, health professionals, farmers and more.
Regarding the second part of your question, very few countries have actually banned the growing of crops. In most cases, GM crops are not approved for cultivation (or growing by local farmers) because a regulatory process does not yet exist in that country. As of 2012, 74 governments had approved either the cultivation of biotech crops in their country or the import of GM food and feed products. The overwhelming weight of scientific evidence demonstrates the safety of plant biotechnology. Even in the European Union, which is widely recognized as the most precautious political authority, governing bodies and scientific bodies have declared a number of specific crops to be safe and published to research reviews concluding that GMOs are at least as safe as conventional crops.