Offspring sex ratio studies of mammals: Does publication depend upon the quality of the research or the direction of the results?

Alternative evolutionary hypotheses concerning a female's offspring sex ratio predict opposing deviations from unity. I suggest that researchers are more likely to attempt to publish sex ratio data when post-hoc analyses reveal significant deviations from unity, and that published studies reporting deviations from unity are more widely read than studies reporting no deviations. As a result, the scientific literature represents a biased sample of the occurrence of skewed offspring sex ratios in nature. The merits of sex ratio studies should be evaluated independently of the direction of the results or the presence of significant deviations from unity. Investigators must be encouraged to publish sex ratio data from long-term studies.