Here are some of the Benefits:
From Crops:
1/ Enhanced taste and quality
2/ Reduced maturation time
3/ Increased nutrients, yields, and stress tolerance
4/ Improved resistance to disease, pests, and herbicides
5/ New products and growing techniques
From Animals:
1/ Increased resistance, productivity, hardiness, and feed efficiency
2/ Better yields of meat, eggs, and milk
3/ Improved animal health and diagnostic methods
From Environment:
1/ "Friendly" bioherbicides and bioinsecticides
2/ Conservation of soil, water, and energy
3/ Bioprocessing for forestry products
4/ Better natural waste management
5/ More efficient processing
From Society:
1/ Increased food security for growing populations
Controversies
The Safety:
Potential human health impact: allergens, transfer of antibiotic resistance markers, unknown effects Potential environmental impact: unintended transfer of transgenes through cross-pollination, unknown effects on other organisms (e.g., soil microbes), and loss of flora and fauna biodiversity
Access and Intellectual Property
1/ Domination of world food production by a few companies
2/ Increasing dependence on Industralized nations by developing countries
3/ Biopiracy—foreign exploitation of natural resources
Ethics
1/ Violation of natural organisms' intrinsic values
2/ Tampering with nature by mixing genes among species
3/ Objections to consuming animal genes in plants and vice versa
4/ Stress for animal
Labeling
1/ Not mandatory in some countries (e.g., United States)
2/ Mixing GM crops with non-GM confounds labeling attempts
Society
1/ New advances may be skewed to interests of rich countries