The retraction last month (see Nature 512, 338; 2014) of the paper 'Generation of pluripotent stem cells from adult human testis' by S. Conrad et al. (Nature 456, 344–349; 2008) has caused some confusion in the scientific community because of its ambiguous wording, which does not serve the purpose of formally amending the scientific record.

Pluripotency is a well-defined property of stem cells both in vivo and in vitro (see, for example, J. Nichols and A. Smith Cold Spring Harb. Perspect. Biol. 4, a008128; 2012). However, the retraction statement refers to the cells derived in the original paper as being “pluripotent to some level”, which wrongly implies that there are different degrees of pluripotency. Such scientific sloppiness is misleading and runs counter to rigorous, evidence-based presentation of results (see, for example, Nature 510, 187–188; 2014 and E. Cattaneo and G. Corbellini Nature 510, 333–335; 2014).

Furthermore, it is unclear what the statement “the original conclusions are not as robust as presented in the original paper” actually means — for example, it could imply that some or all of the earlier conclusions are not entirely invalidated. In which case, we think that those details should have been specified.