RESEARCH QUESTION: Does the ovarian response and the distribution of genetic variants in genes involved in folliculogenesis and steroidogenesis differ according to patients' ethnicity? DESIGN: This was a post-hoc analysis of a prospective, multicentre, multiethnic study including Vietnamese and White patients aged less than 38 years with normal ovarian reserve undergoing their first or second ovarian stimulation cycle. All participants received a fixed dose of 150 IU recombinant FSH in a short antagonist protocol. Genotyping was performed for 67 predefined genetic variants related to folliculogenesis, steroidogenesis and folate metabolism. Ovarian response parameters were compared between ethnic groups. RESULTS: A total of 368 participants were included. Compared with White participants, Vietnamese patients had a shorter duration of stimulation (8.86 ± 1.24 versus 9.60 ± 1.45 days; P < 0.001), lower consumption of recombinant FSH (1329.00 ± 186.64 versus 1439.29 ± 217.30 IU; P < 0.001) and higher oestradiol concentrations on the day of triggering (2808.62 ± 1963.27 versus 2089.29 ± 1175.05 pg/ml; P < 0.001), despite a lower number of growing follicles (15.30 ± 4.55 versus 17.58 ± 6.98; P < 0.001). The number of oocytes retrieved did not differ between groups. Principal component analysis based on single-nucleotide polymorphism frequencies showed a separation of individuals consistent with self-reported ethnicity. CONCLUSIONS: Ovarian response to exogenous FSH differs between Vietnamese and White patients with normal ovarian reserve. Variations in the distribution of genetic variants involved in folliculogenesis and steroidogenesis may partly contribute to these differences and provide a basis for future pharmacogenetic models and the progressive individualization of ovarian stimulation strategies.