Can maternal postpartum testosterone and estradiol retrospectively predict the offspring's sex at birth? A cross‐sectional study in Ghana

The selection of X‐ or Y‐bearing spermatozoa during fertilization may depend on maternal circulating sex hormones. The zona pellucida of the developing oocyte is adapted to be selective for the Y‐bearing spermatozoa when maternal circulating androgens are relatively high. This study sought to determine whether maternal postpartum testosterone and estradiol can retrospectively predict the offspring sex at birth. The study was cross‐sectional from December 2020 to April 2021 at the Reproductive and Child Health unit in Tamale. The participants were part of a previous study and comprised 178 mother–offspring dyads (mother–daughter = 90, mother–son = 88). The mothers were between the ages of 18 and 35 years and had a median (interquartile range‐IQR) postpartum interval of 111 (60–187) days. A single venous blood sample was drawn from the mothers between 8.00 am and 12.00 pm local time on each day to reduce diurnal variation. Postpartum serum estradiol, testosterone, and sex hormone‐binding globulin were assayed using the ELISA technique. The serum total testosterone and the testosterone‐to‐estradiol ratio (TT: E2) were higher in mothers with sons while estradiol was higher in mothers with daughters (p < 0.050). The total testosterone and TT: E2 did not markedly differ by their area under the curve (AUC: 0.91 and 0.99, respectively) but both were higher than the AUC of estradiol (0.72). The Sensitivity was 97.7%, 97.7%, and 94.5% and specificity, 88.9%, 40.0%, and 95.5% at cutoff points of >1.659 nmol/L, ≤141.862 pmol/L, and > 31.5, respectively for total testosterone, estradiol, and TT: E2. The maternal testosterone‐to‐estradiol ratio may be more predictive of offspring sex at birth than either testosterone or estradiol alone.