Claims are being made that man will be able to eliminate genetic defects and eventually "control his own evolution" by a combination of eugenics and specific alterations in his genetic material. While eugenics, or controlled human breeding, is possible, its beneficial effects would be limited or doubtful, and its practice would be socially unacceptable by the majority of the population. In vitro fertilization with subsequent in utero implantation of the resultant blastocyst may some day be possible, but success may be limited, and the method most likely would be fraught with many dangers for the developing embryo. Insertion of healthy genetic material into cells that are genetically defective would have limited benefit even if successful, and the results would more likely be disastrous rather than beneficial. While correction of faulty genes by "genetic surgery" may be theoretically possible, insurmountable technical difficulties will almost certainly forever prevent its use. The idea that man may someday be able to alter specific human characteristics and thus "control his own evolution" is seen as science fiction rather than as serious science.