It has been suggested that transgenics and vertebrate cloning have a role to play in conservation. Now is the time to evaluate their risks and benefits, before these technologies are widely implemented in our field. Direct risks of transgenics include escape and introgression of transgenes into wild populations; weedy invasion by transgenic organisms; toxicity or pathogenicity of engineered organisms and their products; and human error in the field testing and tracking of transgenic organisms. Indirect risks include environmental effects of increased herbicide use; the danger that engineered organisms may aid the development of bioweapons; the likelihood that gene patenting will lead to the privatization of natural resources; and the diversion of support from less glamorous forms of conservation. Formal risk assessments are commonly used to evaluate transgenic procedures, but our incomplete understanding of both ecosystem processes and the action of transgenes renders most of these assessments scientifically and socially unjustified. Nevertheless, a few, low-risk applications of transgenics may be possible: for example, "super-sterile" ornamental cultivars. Vertebrate cloning poses little risk to the environment, but it can consume scarce conservation resources, and its chances of success in preserving species seem poor To date, the conservation benefits of transgenics and vertebrate cloning remain entirely theoretical, but many of the risks are known and documented. Conservation biologists should devote their research and energies to the established methods of conservation, none of which require transgenics or vertebrate cloning.