Advantages:
The farmer no longer has to use insecticide to kill insects, so the surrounding environment is no longer exposed to large amounts of harmful insecticide.
The farmer no longer needs to walk around with a drum of toxic spray wearing a mask and protective clothing.
Disadvantages:
This type of genetically modified corn will poison the insects over a longer period than the farmer who would spray the crops once or twice. In this way the insects can become accustomed (or resistant) to the poison. If that happens both crop spraying and the use of genetically modified Bt-corn become ineffective.
A variety of insects are at risk of being killed. It might be predatory insects that eat the harmful ones or, perhaps attractive insects such as butterflies. In the USA, where Bt-corn is used a great deal there is much debate over the harmful effects of Bt-corn on the beautiful Monarch butterfly.
Cotton and potatoes are other examples of plants that scientists have , genetically modified to produce insecticide.
Golden rice
Golden rice is genetically modified rice that now contains a large amount of A-vitamins. Or more correctly, the rice contains the element beta-carotene which is converted in the body into Vitamin-A. So when you eat golden rice, you get more vitamin A.
Beta-carotene gives carrots their orange colour and is the reason why genetically modified rice is golden. For the golden rice to make beta-carotene three new genes are implanted: two from daffodils and the third from a bacterium