Gender at birth and meteorological factors

Abstract

Objective. In a previous study, we showed that the ratio of gender at birth (M/F ratio) appeared to vary by latitude. We postulate that meteorological factors may be responsible for this variation. In this study, M/F ratio in a central Mediterranean island were correlated to latitude dependent meteorological factors.

Design. The 1957–1998 live birth monthly sex ratios in Malta were correlated with mean monthly temperatures and mean monthly bright sunshine hours.

Results. A positive but not statistically significant correlation was found between M/F ratios and mean monthly temperatures and sunshine hours even over the narrow range of meteorological values investigated.

Conclusions. While no significant trends could be confirmed, the results suggest that M/F ratios may be linked to meteorological factors influenced by latitude. Further studies in countries with a wider mean monthly meteorological value range may confirm or exclude this hypothesis.