Advantages of a standard method for research on reproductive effects of occupation.

A recent review of the literature identified several common methodological weaknesses in studies of the effects of occupational exposures on male and female reproductive processes. This paper suggests a strategy which addresses these problems, by the use of a standard method. The potential benefits include increased measurement reliability and statistical power, together with a systematic study of expected (background) rates, confounding effects, types of exposure and selection effects. Particular advantages are the avoidance of designating a group as non-exposed with attendant problems of bias, and in the longer term the study of multiple or rare exposures.