Concerned citizens who are opposed to the planting of Bt corn say that Bt corn can cause cancer and other health ailments, citing the study of Dr. Stanley Ewen and the position paper against the approval of Bt corn commercialization from some faculty members of the University of the Philippines (UP) Manila.

Dr. Ewen is the collaborator of Dr. Arpad Pusztai who prematurely released his findings to the media without being peer-reviewed by the scientific community. Their study purported that GM potato depressed the immune system of rats and caused abnormal changes in the intestines. The study never gained the acceptance of the scientific community, which cited several flaws in the experimental design and analysis.

The faculty members from UP Manila failed to examine the scientific studies submitted to the Bureau of Plant Industry, which formed the basis for Bt corn approval. Their claims were largely unsupported and have little basis. Moreover, the cited concerns have already been answered by peer-reviewed scientific studies. In fact, Bt corn has long been approved by experts in eight countries and the European Union.

Claims were also made by some groups that BT corn threatens our environment. In 2002, about 7.7 million hectares of Bt corn had been planted worldwide, but no single indication of an environmental threat has been recorded. In the US where it has been planted for six years now, no environmental threat has been identified since. Regarding the effect of Bt corn on non-target organisms, it has been shown through scientific studies that the Bt protein from Bt corn acts only against corn borers and other closely related insects (lepidopterans and coleopterans).

Some farmer groups are also concerned that they may be sued if they reuse their Bt corn seed, or if their corn accidentally gets cross-pollinated by a nearby Bt cornfield. These concerns can be laid to rest because there are two Philippine laws that provide adequate protection to our farmers: (1)The Philippine Patent Law, which does not allow plants to be patented, and (2) the Plant Variety Protection Act, which provides the farmers the right to plant, store, sell, or reuse their seeds.