Worldwide, over seven million children have been conceived to date using a variety of assisted reproductive technology (ART) techniques. In Europe, up to 6% of babies are currently conceived using ART (De Geyter et al. 2018). As the use of ART increases, so too does the urgency to understand the long-term implications of these techniques for the later health and well-being of ART-conceived children. To date, the oldest ART-conceived individual is only 40 years old. Although the currently available evidence is broadly reassuring regarding the short-term outcomes of ART-conceived pregnancies, there is, as yet, little data about outcomes in adulthood, and no data at all on senescence in humans conceived using ART. However, experiments in rodent models show that fluctuations in the early developmental environment, for example different oxygen tensions (Belli et al. 2019), can alter the normal trajectory of long-term development. The preimplantation embryo appears highly sensitive to tiny environmental fluctuations, perhaps even perturbations as small as opening the incubator (Nguyen et al. 2018). The question arises therefore, as to which ART techniques are most likely to induce the subtle alterations in the normal course of early embryonic development that may be linked to potential consequences for long-term development.