Male to female ratio after gonadotropin-induced ovulation.

Two hundred fifty-six children were born in 195 births from 176 women that conceived after human menopausal gonadotropin/human chorionic gonadotropin (hMG/hCG)-induced ovulation. The secondary sex ratio was 50% male to 50% female births, which is not statistically different from the Israeli or Occidental population. The same trend was observed for single births and for twins. Thus, the data presented do not support the reports of increased numbers of female infants in those conceived after induction of ovulation. Factors that are expected to have been shown to affect sex ratio: maternal age at delivery, total number of ampules of hMG/hCG administered in the conceptional cycle, urinary estrogen levels on the day of hCG injection, degree of ovarian hyperstimulation syndrome, and time of insemination in relation to the basal body temperature rise were found to be insignificant. Thus, the hypothesis that a local hormonal environment (gonadotropin or estrogen levels) during hMG/hCG treatment possibly affects sex selection was not confirmed.