Age-standardized dizygotic twinning rates correlate positively and significantly with latitude.
Usage
data(Dizytwin)
Format
A data frame with 19 observations on the following two variables.
Latitude
Geographical latitude in Europe.
DZT_Rate
Dizygotic twinning rates across the countries.
Details
In Europe, both mean birth weight and age-standardized dizygotic twinning rates correlate positively and significantly with latitude. It seems possible that these two sorts of correlation have explanations in common via pituitary action.
Source
James, W. H. (1985). "Dizygotic twinning, birth weight and latitude". Annals of Human Biology,12, 441–447.