Are the GMO dangerous for health ?
We don't know.
Indeed, the detractors of the GMO advance that they present important risks. They are based on the fact that the GMO produce new proteins, unknown factors in nature. However the proteins which we consume normally are the fruit of a long evolution and our organization is thus adapted there. These new proteins appear suddenly without the animals undergoing parallel evolution. For this reason, we don't know the effects that the GMO can have on our cells. However, no study really could accuse the GMO, it on what the producers rest. The question thus remains unanswered.

Do the GMO make it possible to decrease the price of the production ?
Yes and no.
Indeed, the producers of GMO insist on the fact that a plantation of GMO is less expensive than a traditional plantation, for example because the expenses in pesticides are reduced. But it's also necessary to take into account another factor : let us consider a corn farmer. From one year on the other, it will be able to replant a part of its production which will give new corn. Thus, he doesn't need to repurchase seeds each year, his production is autonomous. With the GMO, produced by commercial firms, it is different because the seeds are protected by licences* : the farmers must each year repurchase seeds. The GMO are thus not inevitably a financial advantage.

Are the GMO a solution against the hunger in the world ?
We don't know.
The producers of GMO support this thesis. They are based in particular on the example of golden rice, a variety of genetically modified rice which pushes with much less water. This GMO thus allows the countries in the Third World to increase their production up to three times more. The opponents with the GMO answer by announcing that the hunger in the world is not a problem of production, which would be sufficient, but of distribution. They remember a report of UNO showing that the increase of the global prodution of cereals in 1990 was 50 % higher than the increase of population. Other example : every year, the Brasil sells 11 millions of tonns of soya, whereas 10 % of its population is underfed.
However, this thesis was not shown yet. On the other hand, one could highlight a major defect of golden rice : being produced too quickly, it exhausted certain grounds become unfertile for several years (according to Sciences et Avenir number 703, September 2005).

Is the production of GMO controlled ?
The first reason is that the GMO can infect normal fields. For example, certain GMO are conceived to naturally produce pesticides and weedkillers. They thus become very resistant and when seeds pass accidentally in another field (for example by the intermediary of bees or ground water), they is very difficult to remove them (still should it be known that they are there). In the case of infection of a field by another genetically modified field, certain countries as Germany obtained a legislation making the farmer for GMO responsible.
Moreover, it happens that GMO are planted by error. The American firm Syngenta planted on unauthorized corn on 150 km2. This corn (Bt10) has been sold by error during four years. Previously there had been the case of StarLink, an other corn only authorized for the animals but which had been found in the human food chain (according to Sciences et Avenir Internet, March 23, 2005).

Do the GMO threaten the biodiversity ?
Yes and no.
Great Britain carried out tests named FSEs (Farm Scale Evaluations) to evaluate the effects of the transgenic cultures. The results published in March 2005 show that the bees and the butterflies are fewer in the fields of transgenic colza. In the same way, in October 2003, the Royal Society had published a study relating to 60 different sites and showing that genetically modified colza and the beet decreased the biodiversity.
However, other studies invalidate this conclusion. It seems that it depends on the used GMO and on the local properties (according to Sciences et Avenir Internet, March 22, 2005 and Sciences et Avenir number 703, September 2005).

* Some people wanted to produce infertile GMO, in order to make it impossible, to reuse the seeds. Fortunately, this strategy named « terminator » has been abandonned, because it was unpopular.