Sex differences claimed to be bad science

Caryl Rivers and Rosalind C. Barnett write:

Are single-sex classrooms the magic bullet that will produce academic achievement in public schools? Or are they simply a trend based on bad science and even worse public policy? ...

The claim: Boys are biologically programmed to focus on objects, making them predisposed to math and the understanding of systems, while girls are programmed to focus on people and are best suited for relationships. Leadership and understanding of math and science come naturally to boys, while girls are built for caring for others.

The facts: This idea was based on one study of day-old babies in which the boys looked at mobiles longer and the girls looked at faces longer. The study was demolished by Elizabeth Spelke, an expert on infant cognition and co-director of the Mind, Brain and Behavior Interfaculty Initiative at Harvard. The experiment lacked critical controls against experimenter bias, Spelke said.

Maybe that experiment lacked controls, but there are plenty of others. Here is a Spelke debate on a related subject.