The proposition that human sperm quality is in secular decline has achieved near-recognized status in reproductive medicine, driven largely by high-profile meta-analyses and certain individual studies reporting downward trends in sperm concentration and total motile count over recent decades. This paper argues that the evidentiary foundation for this conclusion is substantially weaker than its prominence in the literature suggests. Specifically, I contend that the apparent decline in sperm parameters is, in large part, an artefact of comparing heterogeneous data generated by methodologically non-equivalent assessment techniques across time or geography. Differences in manual versus computer-assisted sperm analysis, evolving World Health Organization reference criteria, laboratory standardization, population sampling strategies and controls over abstinence intervals collectively introduce systematic variance that can mimic or amplify the appearance of biological deterioration. Until these methodological confounders are rigorously partitioned from biological signals, conclusions about genuine spermatogenic decline remain premature.

Embryo selection is a key determinant of success in assisted reproductive technology (ART). Among recent advancements, time-lapse imaging (TLI) and preimplantation genetic testing (PGT) have emerged as valuable tools for improving embryo assessment. TLI enables continuous, non-invasive observation of embryo development, providing detailed morphokinetic signatures that, when validated, can aid in ranking developmental patterns based on their likelihood of implantation. In contrast, PGT is a method designed to evaluate the genetic composition of IVF embryos before transfer. While both technologies can be effective individually, their combined application may offer a synergistic approach that addresses the limitations of each method when used in isolation. The integration of TLI and PGT may allow for a more informed and accurate embryo ranking. This synergy has the potential to improve implantation rates, clinical pregnancy outcomes and live birth rates, while also supporting single-embryo transfer strategies and reducing associated risks. This article reviews the current understanding of the combined use of TLI and PGT. It highlights their clinical advantages, limitations and future potential in optimizing outcomes and workflow in ART.

The 2025 International Glossary on Infertility and Fertility Care defines pregnancy as 'a state of reproduction beginning with implantation of an embryo and ending with the complete expulsion and/or extraction of the products of implantation'. This implantation-based definition is clinically useful, particularly for assisted reproductive technology ART, registries and outcome reporting. However, it also leaves a biologically relevant interval - between fertilization and implantation - outside the term 'pregnancy'. This interval is not a semantic void: it includes fertilization, cleavage, blastocyst formation, embryo-maternal signalling in vivo, and embryo culture in vitro. This commentary will argue that the Glossary would benefit from a more explicit distinction between pregnancy as an implantation-dependent clinical state, and post-fertilization preimplantation embryonic development as a biological phase. Such clarification would not require abandoning implantation-based definitions for clinical reporting, but would reduce ambiguity in counselling, reproductive pharmacology, ethics and public communication. A stage-specific terminology may better serve both scientific precision and transparent discussion of interventions that act before fertilization, after fertilization but before implantation, or after implantation.