2011 studies by Christopher Badcock PhD suggested that the Y likely carries 100 or so genes with no evidence that any are linked to cognitive ability. While the X carries around 1,200-odd genes, with mounting evidence that at least 150 of these genes are linked to intelligence, and definite evidence that verbal IQ is X-linked. Some studies have also suggested that a father’s X-chromosome genes may be responsible for much of the development of the brain’s limbic system, while a mother’s X-chromosome genes may be more related to cognitive abilities. (But the father got his X from his mother . . .) See what I mean? Some define intelligence simply as the ability to solve problems. But to solve problems, the limbic system is activated as well because the brain works as a whole. Even if intelligence is closely linked to rational thinking functions, it is also influenced by intuition and emotions. While intelligence levels impact the ability to solve problems, effective problem-solving involves cognitive as well as emotional abilities. I guess we’ll just need to stay tuned.