[Sex differences in mortality - time to take a second look].

Ever since mortality has been measured, the existence of a female survival advantage is well known. This topic reached particular interest with the widening of the male-female survival gap during the general decline of mortality in the 20(th) century to an extent of seven years. Only in the last 20 years has a slight narrowing of this gap been observed. The numerous examinations of these sex differences in mortality can be classified into two main explanation categories: the biological and the behavioral or environmental explanations. While in the past, scientists searched for the responsible factors solely in one of these complexes, it is obvious today that the cause of this phenomenon can only be found in a multi-causal context. This article describes the current knowledge and summarizes the most important of them inside the framework of more current research which has enabled researchers to exclude the non-biological factors in comparing female and male survival patterns. Those indicate the existence of a female biological advantage, which however should not exceed a difference of 1-2 years. Consequently, the rest should be due to behavioral and environmental factors. But the additional existence of a cohort effect of people born between 1930 and the mid 1940s with a significant higher male excess mortality often remains unrecognized. This effect could lead again to a widening of this mortality gap in the near future. However, in the long term, we should expect a further decline of sex differences in mortality closer to the biological level due to the continuous approximation of female and male life styles and sex-specific mortality risks.