Differences in science achievement between males and females have been examined either directly or indirectly in a variety of studies. This investigation reviewed a quantitative synthesis of correlational research on science affect, ability, and achievement conducted by Steinkamp and Maehr. Their findings were reassessed by employing a meta-analysis approach which used tests for fitting categorical models to effect sizes. The reexamination focused on explanations of the reported differences in science achievement between males and females as well as on the role of measurement variables in the size of the gender differences. Results indicated that though gender differences tended to favor males, even significant differences were slight, and gender differences for many subsets of studies were not significant. The size of the gender difference depended in part on the science subject matter being tested and also on the type of measure used in the studies. A reference list and a list of synthesized studies are appended. (ML)