GMOs are the most controversial area of science, with genetic engineering widely accepted for medical uses like insulin but more debated for food and agriculture. While humans have modified plants and animals for over 1,000 years through selective breeding, GMOs are seen as different because they are based on inserting beneficial traits using biotechnology rather than natural selection. GMOs could help increase crop yields needed to feed a growing population, make plants more resistant to pests and diseases, and engineer crops that can withstand climate change. However, some argue GMOs could lead to "super bugs" and "super weeds" resistant to pesticides and have unintended consequences.