（1）2050, the world’s population （2）to rise to 9 billion from just over 7 billion currently. Proponents of genetically modified foods say they are safe and can boost harvests （3）in bad conditions by protecting against pests, weeds and drought. This, they argue, will be essential to meeting the needs of a booming population in decades to come and avoiding starvation. （4）Doug Gurian-Sherman, senior scientist for the food and environment program at the Union of Concerned Scientists, an advocacy group, said genetic engineering for insect resistance has provided only a modest increase in yields since the 1990s and drought-resistant strains have only （5）reduced losses from drought.