Do males and females differ in general intelligence? Lynn (1994, 1998) and I (Mackintosh, 1996) agree that the answer to this question must depend on the answer to two prior questions: what is the definition of general intelligence, and what tests best measure it? Our disagreement arises partly from different answers to these prior questions, but also from differences in our reading of some not wholly consistent evidence. What answers might one give to these prior questions? They are not independent, for a possible (severely operational) definition of general intelligence is that it is a person's score on one particular IQ test battery. Let us start with that simple possibility.