Correction to: Nature Methods https://doi.org/10.1038/s41592-023-02066-9, published online 6 December 2023

In the version of the article initially published, in Fig. 2b, the United Kingdom was classified as “Definition denotes fertilization or use of an egg”. This has been corrected to “Definition denotes any method of creation” (Fig. 1) as the definition of an embryo in the HFEA reads “references to an embryo include an egg that is in the process of fertilisation or is undergoing any other process capable of resulting in an embryo”1 [italics ours]. This implies that embryos include but are not limited to structures that derive from an egg.

Fig. 1
figure 1

Revised Fig. 2b.

Notably, the example of the UK underlines the importance of incorporating local expertise regarding legislative history and case law into interpretations of what can and cannot be classified as an embryo. While the HFEA definition does not explicitly incorporate a reference to potentiality and is hence not classified as such in this figure, a related 2003 ruling by the House of Lords does include a reference to potentiality when it stipulates that an embryo is “a live human organism containing within its cell or cells a full set of 46 chromosomes with the normal potential to develop and, if planted in a woman, to become a foetus and eventually a human being”2. As Fig. 2 is based on an analysis by Matthews & Moralí3 that excluded legislative history and case law, this is not reflected in the amended figure.