I won't pretend to have numbers at my fingertips, but I do know that, at the other end of exceptionality, there are many years of research finding that girls are underidentified with ADHD, LD, and intellectual impairment. I think that socio-behavioral expectations for girls, and their ability (as a group) to use those expectations to appear more normative (from both ends of the bell curve) are huge factors. It doesn't help that many of the diagnostic criteria for exceptionalities (like much of psychology) have been developed based on studies of males only or predominantly. I have known many female students whose best cognitive assessment was well under - 2 SD, but were perceived as being essentially normative in intelligence --if a little scatter-brained-- by both peers and teachers. But guess what, she's not lazy, overly social, or distracted--she literally cannot comprehend the material! Boys, on the other hand, (especially those of color) are overidentified as ADHD, intellectually impaired, and emotionally/behaviorally impaired.
I wonder if teachers are more surprised by boys excelling academically in the primary years, more likely to treat their verbal skills as exceptional (because they expect girls to be verbal, and boys not to be), as well as more likely to notice behavioral symptoms of instructional mismatch in boys.
I would agree with 2GK that many teachers have misconceptions about the signs of giftedness. Back when I was on the gifted screening team, teachers routinely referred bright average kids and overlooked truly gifted kids.
