During the early twentieth century, the scientific consensus shifted to the view that gender plays no role in intelligence,  but men consistently overestimated their IQs and women consistently underestimated their IQs.
Generally, females show advantages in verbal fluency, perceptual speed, accuracy and fine motor skills, while males outperform females in spatial, working memory and mathematical abilities [ 23 ]. M: Human men generally tend to be bigger than women, and this is reflected in brain size.
For example, they found female subjects performed better on verbal abilities while males performed better on visuospatial abilities.
They summarized his conclusions as he quoted, "No evidence was found for sex differences in the mean level of g or in the variability of g. Visual Reaction Time: Subjects pressed the space bar of the computer key-board on the appearance of a green signal on the screen, for 5 times.
The reason, they said, is simple: Girls used to take fewer advanced math courses than boys, but now they are taking just as many.