It is common knowledge that autistic women often mask much more than autistic men, and that this is why they're under-diagnosed. However, I have a new theory. It could be that autistic men mask but in a different kind of way. First, let's just describe two kinds of autists: normie autists and the usual high-functioning autists.

Normie autists are the ones who are overrepresented on social media about autistic people, who are the most vocal about their autism, who disproportionately post on r/autism, who are more self-diagnosed (but could be diagnosed), and who are the most talked-about group on the media. They often can mask well, and even if they don't mask, still have great conversation/social skills, don't have arrested development, are disproportionately genderfluid, have the ability to know words, things, and activities that everyone their age knows, etc. These autists are the autists you could meet in everyday settings. Autistic women often are these autists, and autistic women mask quite well and have innate good social skills. These are the only autists I see have relationships, have a plentiful social life, adjust to adulthood and whatnot. This explains why autistic women often have better social lives, more sexual/romantic experience, and are better with getting into college or getting a job.

The usual high functioning autists are the silent, ignored majority of high functioning autistic men. Most autistic men and a minority of autistic women fall under this category. These people often have really bad social skills and can't maintain a conversation, sometimes won't know what is socially appropriate, cannot mask to save their live (at least by what is normally defined as masking), have arrested development, have nasal voices and exaggerated vowel pronunciation, are very asocial and reclusive, are almost always cisgender, have an interest in stuff like Nintendo or something in adulthood, have delayed vocabulary or don't know certain slang words or names of activities or things in life everyone their age knows, are more likely to live with parents, often are virgins with no social life, and you can tell they're autistic within seconds. These autistic people never really go out much, and you can only meet them if you sign up for an autism group therapy program. You rarely meet them in everyday settings. These are the usual ones I've met in life. These guys I never see have relationships, and when I asked them, they all were 100% inexperienced despite being in their mid-20s or older. They often couldn't move out of their parents' houses and often have no social contact with the world.

The normie autists are the ones who typically mask (as how it's usually defined), and are still good socially when they don't, and they're disproportionately women (but sometimes men), whereas the usual high functioning autists I've met are usually men 90% of the time (but a minority are women).

Autistic women vs autistic men's social/career lives

Multiple studies show that autistic men are more socially stigmatized by people than autistic women, even when controlling for masking or autism severity. The researchers concluded being a woman must've been the reason. Both male and female participants rated neurotypical women as the most likeable, least awkward and most worth hanging out with, with neurotypical men coming in second place, and autistic women being rated slightly less likeable, slightly more awkward, and slightly less worth hanging out with than neurotypical men, and autistic men being rated far less likeable, far more awkward, and far less worth hanging out with. Autistic women are far more likely than autistic men to have had sex, relationships or their first kiss before, and the sexually inactive women were often disinterested in sex whereas most autistic men who didn't have sex had an interest in it. Other evidence shows that autistic women are much more likely to have postsecondary education and struggle a lot less with finding jobs. Nonetheless, autistic women were more likely to prefer having no company. Despite this, autistic women often are much more talkative and better socially, whereas autistic men often are quiet, socially inept, asocial and reclusive. Many people might argue these statistics show people who are diagnosed and many autistic women are undiagnosed, but the issue is that undiagnosed people sometimes, but not always, might be less evidently autistic, so if it included all autistic people and autistic women are under-diagnosed, the gap between how successful the women are vs the men would be bigger, not smaller.

Theory: the usual high functioning autists, who are mostly men, probably mask as often as normie autists, who are mostly women, but in a different way.

A lot of evidence has shown that autistic women mask more and that they are much better socially. This makes sense. I've personally noticed that autistic women talk more and have better conversations, but the autistic men I spoke to often, but not always, are very asocial and quiet. Even the ones who talk a lot often are socially inept and cannot mask (at least masking in how it's normally defined). You can easily tell they're autistic. So why is this if autistic women are possibly more introverted? A study observing autistic kids found:

The results indicate that the female social landscape supports the camouflage hypothesis; girls with autism spectrum disorder used compensatory behaviors, such as staying in close proximately to peers and weaving in and out of activities, which appeared to mask their social challenges. Comparatively, the male landscape made it easier to detect the social challenges of boys with autism spectrum disorder. Typically developing boys tended to play organized games; boys with autism spectrum disorder tended to play alone.

It is possible that autistic men mask as often as autistic women, but differently. Autistic women, who are often the normie autists I described, often have good social skills and know how to make good conversations. As a result, they know how to pass off as neurotypical when interacting with people and know how to keep their disability under control. Autistic men, who are the usual high functioning autists, often have very bad social/conversation skills and cannot act neurotypical at all, so they can't have the ability to mask in the way masking is traditionally defined. People say this is due to socialization, but autistic boys faced more social stigma growing up, and being socialized a certain way doesn't completely affect your disability, so this can't be the only reason autistic women succeed more at masking or are better socially. It could be their autism, innately speaking, is not as socially disabling because autistic women's autism naturally manifests differently.

It could be that autistic men often just keep their mouth shut, don't do anything and act very asocial because they have innately bad social skills, cannot blend in socially and are shy and cannot face the music, so they socially withdraw to avoid social consequences, whereas autistic women, regardless of shyness, will face the music, use their innate good social skills and will mask as a neurotypical girl to blend in. Masking and acting neurotypical might be distressing, but so is having to act quiet out of shyness. There have been times where I have acted quiet when I didn't know what to say or was socially clueless, and this might explain why many autistic guys I meet do this far more often than me, because they struggle socially more than even me, and I struggle socially way too much anyway. Maybe they aren't genuinely asocial, but are socially withdrawing to avoid social stigma. Just remember, even with dating, evidence shows that many love-shy men have Asperger's (at least 40%).