One of the reasons for not including maternal care is due
to methodological issues such as examining childcare characteristics as
predictors (e.g., existence of childcare, onset of childcare, or amount of
childcare), which makes maternal care difficult to operationalize and
to compare to non-maternal childcare. However, even in the modern
Western world almost half of children still being cared by their
mothers, especially in the first couple of years. Comparing children
who are cared in non-maternal settings with children who are fully
cared by their mothers would improve the understanding of the
impact of non-maternal childcare on child development.