Men have greater general mental ability....

One of the authors of this study is Canada...I haven't seen much mention of this in the Canadian press.

A study of 100,000 17- to 18-year-olds on the Scholastic Assessment Test published in the September 2006 issue of the journal Intelligence, has confirmed a surprising new finding-that men have a 4- to 5-point IQ advantage over women by adulthood. Because girls mature faster than boys, the sex difference is masked during the school years, which explains why the sex difference was missed for 100 years.

A study published in the September 2006 issue of the journal Intelligence analyzed 145 items from the Scholastic Assessment Test (SAT) in 100,000 17- to 18-year-olds and found a male IQ advantage of 3.63 points.

It also found that the g factor--the general factor of mental ability underlay both the SAT Verbal (SAT-V) and the SAT Mathematics (SAT-M) scales with the congruence between these components greater than 0.90, and that it was the g factor that predicted student grades better than the traditionally used SAT-V and SAT-M scales.

The male and the female g factors were congruent in excess of .99, and they favored males to an equivalent of 3.63 IQ points.

The male-female differences were present at every socioeconomic level, and across several ethnic groups.

The average male advantage was found "throughout the entire distribution of scores, in every level of family income, for every level of fathers' and of mothers' education, and for each and every one of seven ethnic groups," said J. Philippe Rushton, professor of psychology at the University of Western Ontario, one of the authors of the study.