In this study, we investigated 1) the role of pH in sex determination (i.e., pH-mediated sex determination, namely,PSD); 2) the potential of PSD to be maintained across generations and in the natural environment; 3) the effects of low pH on reproductive traits, fecundity, and offspring development; and 4) the existence of candidates of sex-specific genes and the potential molecular mechanisms underpinning PSD. For this, we used the Portuguese oyster (Crassostrea angulata, also known as Magallana angulata), as a model system.This dataset is included in the OA-ICC data compilation maintained in the framework of the IAEA Ocean Acidification International Coordination Centre (see https://oa-icc.ipsl.fr). Original data were provided by the author of the related paper (see Related to) to the OA-ICC data curator. In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2024) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI). The date of carbonate chemistry calculation by seacarb is 2025-04-01.