What are some biosafety issues concerned with genetically modified crops?

Some of the important biosafety issues concerned with GMO are listed below.
* There is a risk of altering the fundamental nature of vegetables and fruits.
* Transfer of allergens or toxic substances into human beings and other animals.
* A risk of gene pollution due to new gene transfer into related local varieties through natural out crossing results formation of super weeds.
* Super weeds may become resistant to weedicides.
* They may bring about changes in natural evolutionary patterns.