1. James, W. H. The human sex ratio. Part 1: A review of the literature. Hum. Biol. 59, 721–752 (1987).
2. Mackenzie, C. A., Lockridge, A. & Keith, M Declining sex ratio in first nation community. Environ. Health Perspect. 113, 1295–1298 (2005).
3. Kaba, A. J. Sex ratio at birth and racial differences: why do black women give birth more females than non-black women? Afr. J. Reprod. Health 12, 139–150 (2008).
4. Chahnazarian, A. Determinants of the sex ratio at birth: review of recent literature. Soc. Biol. 35, 214–235 (1988).
5. Dodds, L. & Armson, B. A. Is Canada’s sex ratio in decline? CMAJ 156, 46–48 (1997).