In this work we analyze the combined effects of gender, age and academic rank on the propensity of individual scholars to diversify their scientific activity. The aspect of research diversification is measured along three main dimensions, namely its extent and intensity and the cognitive relatedness of the fields of diversification. We apply two regression models to the dataset of scientific output of all Italian professors in the sciences over the period 2004-2008. The aim is to understand how personal and organizational traits can influence individual behaviors in terms of research diversification. Among other considerations, our findings urge caution in identifying research diversification as a co-determinant of the gender productivity gap between males and females.