Benefits

• Crops and Animals
• Better taste and quality
• Faster to mature, greater productivity
• More nutrients and yields
• Resistance to pests
• Immunity from diseases and herbicides
• New goods (medicine) and cultivation techniques
• Better, stronger health (withstand frost and extreme salty conditions)
  
• Society - "safer" food to an expanding population

Controversies

• Plant and Human Health
• Allergens, superbugs/viruses, transfer of toxins, unknown effects
• In the environment, cross-pollination may occur, affecting other organisms, negatively impacting biodiversity
• Economy
• Some companies may seize monopoly of an industry
• Globalization and dependence
• Loss of natural resources
• Countries may take advantage of others (greater gap between rich and poor)
• Ethics
• Altering an organism; humans tampering with nature
• Vegans may eat animal genes in plants
• Feelings of the animals
• Labeling
• Is not universally mandatory (e.g., not in the USA)