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In May 2023, The Guardian announced that babies had been born through mitochondrial replacement therapy (MRT). MRT and its ethical and legal implications have been discussed in the media for over a decade. These discussions have been examined by social scientists and communication scholars. In this article, we seek to determine whether and, if so, how social representations have changed since this announcement. Using thematic analysis and social representations theory, we studied a corpus of 70 English language newspaper articles. Results show three thematic dichotomies: (1) moderation vs. sensationalism; (2) ontologising vs. de-ontologising MRT; and (3) using metaphors for persuasion vs. explanation. The societal concern representation largely dominated reporting around 2015 and the hope and opportunity representation was prominent in current reporting. We argue that the hope representation may facilitate greater patient and public acceptance of MRT but that it may also limit awareness, understanding and discussion of its possible risks and limitations.

Abstract The second polar body (PB2) transfer in assisted reproductive technology is regarded as the most promising mitochondrial replacement scheme for preventing the mitochondrial disease inheritance owing to its less mitochondrial carryover and stronger operability. However, the mitochondrial carryover was still detectable in the reconstructed oocyte in conventional second polar body transfer scheme. Moreover, the delayed operating time would increase the second polar body DNA damage. In this study, we established a spindle‐protrusion‐retained second polar body separation technique, which allowed us to perform earlier second polar body transfer to avoid DNA damage accumulation. We could also locate the fusion site after the transfer through the spindle protrusion. Then, we further eliminated the mitochondrial carryover in the reconstructed oocytes through a physically based residue removal method. The results showed that our scheme could produce a nearly normal proportion of normal‐karyotype blastocysts with further reduced mitochondrial carryover, both in mice and humans. Additionally, we also obtained mouse embryonic stem cells and healthy live‐born mice with almost undetectable mitochondrial carryover. These findings indicate that our improvement in the second polar body transfer is conducive to the development and further mitochondria carryover elimination of reconstructed embryos, which provides a valuable choice for future clinical applications of mitochondrial replacement.

Mitochondrial replacement therapy (MRT) in Canada is considered a criminal offense according to article 5(1)(f) of the Assisted Human Reproduction Act (AHRA) (2004). The Act prohibits any practice that modifies the genome of “a human being or in vitro embryo such that the alteration is capable of being transmitted to descendants.” We carried out 32 semi-structured interviews with clinicians, researchers, patient groups, egg donors, and members of the public to explore their attitudes toward the clinical implementation of MRT in Canada. Our interview guide was informed by the socio-ethical, legal, and scientific literature of MRT. We used a thematic analysis to identify and analyze emerging themes and sub-themes. Our findings were divided into five broad themes: (i) an outdated criminal ban, (ii) motives for using MRT, (iii) terminology, (iv) practical and theoretical risks and benefits, and (v) the feasibility of clinical translation in Canada. Although the public and stakeholders’ views on the feasibility of foreseeable translation of MRT in Canadian clinics varied, there was consensus on conducting an overdue review of the current AHRA ban on MRT.

Mitochondrial DNA (mtDNA), as its name implies, is an embodiment of the mitochondrial genetic information that constitutes about 1% of the mammalian genome. It fills a vital niche in tracing matrilineality; the mtDNA is inherited solely from the mother and plays a crucial role in genealogical research. Even a single mutation in the mtDNA can have debilitating and life-altering consequences. Mothers carrying mtDNA mutations will inevitably pass it on to the future generation. Three-parent In vitro fertilization (IVF), a breakthrough technique, shows promising potential to prevent mothers with mtDNA defects from passing it on to their future generation, while also maintaining the genetic link to their posterity. In this review, I delve into the intricacies of this technique, compare and analyze the difference between maternal spindle transfer and pronuclear transfer, discuss the prospective therapeutic effects, and highlight the ethical concerns surrounding this procedure. Considering the various challenges and ethics of this contentious technique, the paper seeks to answer the rousing question – Is three-parent IVF the answer to preventing mitochondrial defects?

Canada's Assisted Human Reproduction Act is long overdue for Parliamentary review. We argue that the current regulation of research using human reproductive materials is not proportionate, not responsive to the uncertain threats posed to human and environmental health and safety, and is not considerate of diverse values in a democratic society. We propose tailored regulatory carve-outs for in vitro research for currently prohibited activities, such as gene editing, and for the exercise of Ministerial Discretion for access by Canadians to experimental in vivo interventions that are currently prohibited, such as mitochondrial replacement therapy. Our recommendations are bounded by constitutional constraints that recognize political and practical challenges in keeping oversight of this research under Federal jurisdiction, whether conducted in academic or private sectors. The proposed nuanced regulatory scheme should be overseen by a new national Agency, modeled on a blend of the Canadian Stem Cell Oversight Committee and Assisted Human Reproduction Canada.

The mitochondrial genome is an evolutionarily persistent and cooperative component of metazoan cells that contributes to energy production and many other cellular processes. Despite sharing the same host as the nuclear genome, the multi-copy mitochondrial DNA (mtDNA) follows very different rules of replication and transmission, which translate into differences in the patterns of selection. On one hand, mtDNA is dependent on the host for its transmission, so selections would favour genomes that boost organismal fitness. On the other hand, genetic heterogeneity within an individual allows different mitochondrial genomes to compete for transmission. This intra-organismal competition could select for the best replicator, which does not necessarily give the fittest organisms, resulting in mito-nuclear conflict. In this review, we discuss the recent advances in our understanding of the mechanisms and opposing forces governing mtDNA transmission and selection in bilaterians, and what the implications of these are for mtDNA evolution and mitochondrial replacement therapy.

The transition of new biotechnologies into clinical trials is a critical step in approving a new drug or therapy in health care. Ethically recruiting appropriate volunteers for these clinical trials can be a challenging task for both the pharmaceutical companies and the US Food and Drug Administration. In this paper we analyze the Jewish halachic perspectives of volunteering for clinical trials by focusing on an innovative technology in reproductive medicine, mitochondrial replacement therapy. The halachic perspective encourages individuals to volunteer for such clinical trials under the ethical principles of beneficence and social responsibility, when animal studies have shown that health risks are minimal.