Parental hormone levels and mammalian sex ratios at birth.

  title={Parental hormone levels and mammalian sex ratios at birth.},
  author={William H. M. James},
  journal={Journal of theoretical biology},
  volume={139 1},
I have previously suggested that parental levels of several hormones (gonadotrophin, oestrogen, testosterone) at the time of conception affect the sex of mammalian offspring (James, 1986, J. theor. Biol. 118, 427). In this note it is suggested that progesterone also has such an effect. Clutton-Brock & Iason (1986, Q. Rev. Biol. 61, 339) concluded that variation of sex ratio had been reasonably well established with a number of variables in a number of non-human mammalian species. In this note… CONTINUE READING