Research Article

Gonadotrophin and the human secondary sex ratio.

Br Med J 1980; 281 doi: https://doi.org/10.1136/bmj.281.6242.711 (Published 13 September 1980) Cite this as: Br Med J 1980;281:711
  1. W H James

    Abstract

    A review of published reports showed that the sex ratio (proportion of boys) was low among infants conceived after ovulation had been induced. The difference between the observed sex ratio and an expected one of 0 . 514 was highly significant. These findings suggest that maternal gonadotrophin concentrations at the time of conception directly affect the sex of the zygote.