In many bacteria, the plasmids used in recombinant studies contain the gene conferring resistance to antibiotics.It was feared, during early attempts to effect DNA transplantation, that bacteria would be created that would be resistant to all known antibiotics. The possibility of an uncontrolled plague that would sweep through the human population was only one of many concerns that arose from consideration of the consequences of tinkering with thegenetic apparatus.
Cloning also presents scientific and ethical questions. Since the cloning technique does not involve the usual sexual process for recombining genetic material, it short-circuits a mechanism for providing variability, which in turn deprives the organism of adaptive potential and thus leaves it more vulnerable to selection pressures. Questions also have arisen about the legal status of a possible human clone, since it would be a genetic replica of one individual but would be born to a woman who has provided a foster womb without making a genetic contribution to the clone
Questions exist about who the parents of the clone would be, what family relationships the cloned person would have,etc. These considerations involve the legal and religious communities as well as biologists. In some countries, special panels have been set up to deal with the ethical and biological issues involved in genetic engineering.