onships between the technology and the feared harm, in part by reviewing experience with similar kinds of technologies in the past. For example, in the area of new reproductive technologies we can look to experience with artificial insemination to judge the likelihood of posited harms from a related technology like oocyte, or egg, donation. However, even if people can come to agree about the probability of such posited harms, they may still disagree about the magnitude of harm. In the case of a new technology like human cloning, it is reasonable to demand of opponents that they identify tangible and serious harms of the sort generally required to support a prohibition of research on or use of the new technology. The language of repugnance, used by Leon Kass and apparently endorsed by Callahan, makes clear that they find human cloning deeply offensive, but it does nothing to identify the harms, much less to establish that those harms are of sufficient magnitude to support a public prohibition of human cloning. In a free society, the burden of proof should be on those who wish to prohibit behavior, and mere offense to some people typically is not, nor should it be, sufficient to meet that burden. The possibilities of producing serious human defects raises ethical dilemmas as well as the question of the social responsibility involved in the care of deformed beings produced by human cloning experiments. Fervent pro-cloners like Antinori and Zavos deny there are any risks to cloning humans and claim that there is enough information to proceed with confidence. If pressed to admit there might be mistakes, they simply write them off as necessary means to the end of reproductive freedom and medical progress. Ignoring the availability of frozen embryos and existing children for adoption, they claim the right to reproduce as crucial for human beings, and argue that this right - which in fact does not exist in any social constitution...
