reduced pesticide use suggests that bt crops would be generally beneficial to incrop biodiversity in comparison with conventional crops that receive regular broadspectrum pesticide applications although these benefits would be reduced if supplemental insecticide applications were required gm science review panel at present the production of transgenic and cloned animals is extremely inefficient with high mortality during early embryonic development and success rates of only percent of the transgenic animals born the inserted genes may not function as expected often resulting in anatomical physiological and behavioural abnormalities nrc