Here's the paper I read earlier (and mentioned earlier on this thread) on the CogAT. Basically what this is saying is that there is a large difference between genders in terms of students with extreme scores, especially on the quantitative reasoning section. So the boys have an advantage if the goal of the school is to pick out students who are scoring above, say, the 96th or 98th percentile. I think there is also a gender difference on other sections of the CogAT but not as extreme. I didn't read this again, thoroughly, but I don't believe girls had an advantage in verbal ability.
CogAT is not an IQ test, it's a cognitive abilities test, but this is still significant because so many schools use this test, or similar tests, to identify students as gifted or not. So if the school programs are flooded with gifted boys, and not as many girls, and they are offering services only to students with very high scores, this could be one of the reasons why.
http://www.auburn.edu/~jml0035/index_files/Lohman_Lakin_BJEP09.pdf
I have a hard time believing that the boys are referred for gifted services by teachers more often due to them being disruptive in class, because most teachers seem to refer the perfect high-achievers, thinking they would be successful in a gifted program. A boy who is off-task and always needing re-direction or discipline, would probably just be seen as a troublemaker, and less likely to be successful with advanced work.
