Madao wrote:
The ratio is skewed because there are more cases of boys being diagnosed. It's probably because girls are better at hiding it. Also her behavior might be considered normal in her culture for females. For example a girl might act extremely quiet and submissive. People might pass it off as "She's just being shy". However if a boy were to act that way people would think there is something wrong. Since it's culturally acceptable for little boys (American) to be "loud and aggressive"
People who are more mildy affected, like me, will be better at hiding it, regardless of sex. What does it mean to be better at hiding it, if not to just have a milder case? There could be just as high a proportion of undiagnosed boys with mild cases as there are undiagnosed girls in the same position, it's just that experts have started looking specifically for atypical presentations in the female population, such as less bizarre special interests and the ability to mimic others, and so they're finding them there.
You could also argue that as it's more socially acceptable (or rather, less startling, precisely because people are more used to seeing various symptoms of developmental delay in boys whether they know what they are or not) for boys to have problems getting along with others, doing what they're supposed to do without complaint and being sensitive to others' needs, that there are probably lots of boys who are 'better at hiding it' (mild) who go undiagnosed because only when a girl acts like that would people think there's something wrong.
Again, I do think underdiagnosis of girls and milder cases in general is a real phenomenon, one that's affected me too, and it's good it's being investigated, I just doubt, given the evidence available, that there is in reality exactly the same percentage of girls as boys with ASDs.
Lots of non-neurological conditions affect men or women disproportionately, including common killers like heart disease and breast cancer. It's not an unfamiliar concept in the rest of medicine, it's only in neurology that people assume sex shouldn't make a difference, perhaps because it's not as obvious just how different the male and female brain and hormone levels are on average, as we can't see them. However, there are highly significant differences, and while other things including depression, generalised anxiety and PMDD affect women more than men (PMDD is exclusive to women, obviously) other conditions do appear to be genuinely more common in men, and there is even evidence suggesting why.