This seems to be a complicated subject. Dr. Arthur Jensen, in his "Straight Talk About Mental Tests", says that IQ tests are carefully standardized so that men and women have the same average IQ of 100. However, he says that even when that's not done, the differences in IQ are more in kind than in quantity. He observes that men and women are essentially equal when it comes to the general intelligence, or "g" factor. However, on page 248, he says,
"Males and females differ in certain other abilities, however, The most well-established difference is in spatial-visualization ability--the ability to mentally visualize complex objectx, and to mentally manipulate relationships among objects in three-dimensional space. It is an important ability for geometry, organic chemisry, architecture, structural engineering, and the like. Spatial visualization is also a compnent of mathematical ability, in which wpatial representation of quantitative relationships plays a part in problem-solving proficiency. In the best tests of spatial visualization ability, only about one-fourth of females surpass the average male."
(Note from me: expressed as IQ, men would have an average "spatial-visualization IQ" of 111, compared with 100 for women.)
"The sex difference in spatial ability is evident in childhood, but increases markedly after puberty. There is some evidence that it is related to male hormones and also some evidence that other genetic factors play a part in the sex difference. I don't know of a single expert in this field who believes that cultural and environmental causes--such as the cultural difference in sex-role socialization--is anywhere near adequate fo explain all the evidence related to the sex difference in spatial and mathematical ability.
"Because of the connection between spatial abiltiy and mathematical ability, there is a notable sex difference in the latter as well, and it cannot be explained by differences in amount of exposure to mathematics or differences in motivation to succeed in math."
He goes on to say,
"There are more males than females above IQ 143 (standard deviation = 16) (in the ratio of about 1.2 to 1)." and,
"A great deal of excellent research is being done on this topic at present, and the next few years should see an increase in our knowledge and understanding of these phenomena."
Dr. Jensen's book was published in 1981 and probably written in 1980, so the data is about 20 years old. Using Dr. Gina Losasso's value of 13.6 points of IQ for the standard deviation for women, I arrive at a male-to-female ratio of about 2.66 to 1 for individuals above an IQ of 143--considerably higher than the 1.2-to-1 ratio given in Dr. Jensen's book. This 13.6 number, which agrees with the kinds of numbers I've seen elsewhere for the spread of women's IQ distribution, generates problems of its own when we consider the scores made on the Mega test by the two women who got 46 right out of 48. Logically, their IQs couldn't much exceed about 5 standard deviations (1 in 3,500,000), which would anchor a 46 on the Mega Test at an IQ in the neighborhood of 170. That seems significantly too low. I can believe 176 (1-in-1,000,000 men) to 180 (1-in-3,500,000 men) for a 46 on the Mega Test (or even to 183... 1-in-9,000,000), but I have trouble believing that a 46 isn't indicative of something quite a bit higher than a 170 IQ (1-in-160,000). Of course, it depends upon the kind of material included on the IQ test. If there are no spatial visualization problems, and lots of verbal problems, the ladies might take the lead. But the Mega Test certainly includes its fair share of spatial visualization problems, and the distaff side certainly has certainly done a journeymanlike job of solving them.
The current model for male-female brain differences is that, although women have smaller brains than men, men's and women's brains possess the same number of neurons, but women have less glial (supporting) material. On the other hand, women have a larger corpus callosum (made of glial material) than men. Women appear to use their entire brains for problem-solving, whereas men use specific areas of their brains. (Women will tell you that the only parts of their brains that men use are the parts that deal with sex.) This lesser amount of glial material has been suggested as the root of the male-female difference in spatial visualization.
On the other hand, if hormones play a role at puberty, it's hard to see how this could greatly alter brain structure this late in life. (Testosterone is now being implicated in brain development.)
The bottom line is that I don't have a warm feeling about what little I know about this topic.
Two other observations when considering the CMT testing: both Flynn Effect and the the average age of the Termites at the time they took the CMT (41) would have played a small role in their scores on the CMT-T.