Fearing a non-existing Minotaur? The ethical challenges of research on cytoplasmic hybrid embryos

Ethical arguments concerning human-animal chimera research: a systematic review

Background

The burgeoning field of biomedical research involving the mixture of human and animal materials has attracted significant ethical controversy. Due to the many dimensions of potential ethical conflict involved in this type of research, and the wide variety of research projects under discussion, it is difficult to obtain an overview of the ethical debate. This paper attempts to remedy this by providing a systematic review of ethical reasons in academic publications on human-animal chimera research.

Methods

We conducted a systematic review of the ethical literature concerning human-animal chimeras based on the research question: “What ethical reasons have been given for or against conducting human-animal chimera research, and how have these reasons been treated in the ongoing debate?” Our search extends until the end of the year 2017, including MEDLINE, Embase, PhilPapers and EthxWeb databases, restricted to peer-reviewed journal publications in English. Papers containing ethical reasons were analyzed, and the reasons were coded according to whether they were endorsed, mentioned or rejected.

Results

Four hundred thirty-one articles were retrieved by our search, and 88 were ultimately included and analyzed. Within these articles, we found 464 passages containing reasons for and against conducting human-animal chimera research. We classified these reasons into five categories and, within these, identified 12 broad and 31 narrow reason types.

15% of the retrieved passages contained reasons in favor of conducting chimera research (Category P), while 85% of the passages contained reasons against it. The reasons against conducting chimera research fell into four further categories: reasons concerning the creation of a chimera (Category A), its treatment (Category B), reasons referring to metaphysical or social issues resulting from its existence (Category C) and to potential downstream effects of chimera research (Category D). A significant proportion of identified passages (46%) fell under Category C.

Conclusions

We hope that our results, in revealing the conceptual and argumentative structure of the debate and highlighting some its most notable tendencies and prominent positions, will facilitate continued discussion and provide a basis for the development of relevant policy and legislation.

Value-impregnated factual claims and slippery-slope arguments

Slippery-slope arguments typically question a course of action by estimating that it will end in misery once the first unfortunate step is taken. Previous studies indicate that estimations of the long-term consequences of certain debated actions, such as legalizing physician-assisted suicide, may be strongly influenced by tacit personal values. In this paper, we suggest that to the extent that slippery-slope arguments rest on estimations of future events, they may be mere rationalizations of personal values. This might explain why there are proponents even for strikingly poor slippery-slope arguments.

Emerging ethical perspectives in the clustered regularly interspaced short palindromic repeats genome-editing debate

This paper provides an overview of the ethical issues in the international clustered regularly interspaced short palindromic repeats (CRISPR) genome editing debate from March 2015 to September 2016. We present the regulatory framework for embryo research in the UK, and explain why CRISPR is not a significant break with the past. We discuss the ethical issues arising from CRISPR applications beyond human embryos, namely the use of gene drive-engineered mosquitoes to eradicate diseases, engineering nonhuman animals to harvest organs for human transplant and engineering crops. We discuss the experiments that have demonstrated the technical feasibility of cultivating embryos in vitro for up to 14 days, and possibly beyond this limit, and the ethical issues arising from the proposal to extend the limit beyond 14 days.

Sex and reproduction: an evolving relationship

BACKGROUND

Although sexual activity has, until very recently, been essential to reproduction, this did not preclude the non-reproductive importance of sexual relationships and non-conceptive copulations. Technological advances, however, now allow for both sex without reproduction and reproduction without sex. This review summarizes social and ethical commentaries on the new relationship between sex and reproduction.

METHODS

For each main area discussed, a systematic search was made using (depending on the subject) PubMed, Medline, ScienceDirect, classic books, Google and/or religious websites. The search focused on publications between 1975 and 2009, although some materials from the first part of the 20th century were also utilized.

RESULTS

The classic picture of sex for reproduction and bonding between mating partners is increasingly being replaced by reproduction separate from sexual activity. Although not every advance in assisted reproduction produced, per se, a further separation from sexual intercourse, these two fundamental human activities are today increasingly carried out independently, as reproduction is possible, not only without sex, but even through the intervention of more than two partners. The possibility of reproduction with only one or even no gametes, although highly controversial and not yet feasible, is nonetheless being investigated.

CONCLUSIONS

Technological advances in the field of reproductive biology have enabled couples considered infertile to conceive and have healthy babies, causing a revolution in culture and customs. Today the independence of sex and reproduction is established and in the future human reproduction may move even further away from the sexual act, an option definitely unacceptable to some ethicists.