That depends on the features of each product.  For example, if you are comparing the most sophisticated sanitary napkin with the most economic diaper, perhaps both are as simple; or as complex.  In general terms, when we are talking about similar market segments, a sanitary napkin is much easier to manufacture than a diaper because it does not need as many features.   This is the main reason why a diaper producer can get into the sanitary napkins business easier than the other way around.