Me/gender misconceptions

Here are some things I thought I understood about gender which turned out to be wrong.

• Myth: "Sex" and "gender" are the same thing – that is, The body's sex (biological reproductive role) is the same thing as the individual's gender.
  • Reality: They're highly correlated, but not always the same. When they disagree, you get gender dysphoria.
• Myth: Gender identity is almost entirely socialized – that is, we're taught to be "girls" or "boys" by how we're treated. Your brain doesn't have an innate gender.
  • Reality: It turns out that certain brain structures/wiring are different depending on whether you're male or female – and where gender identity differs from your biology, these differences correlate more closely to identity than to body type.
  • There was a time when I didn't want this to be true, because I thought if brains were different then that would mean my brain would be different from a girl's brain, and that made me sad. It turns out that actually, it means my brain is more like a girl's brain and less like a boy's brain, which makes me happy. (It also fits with, and explains, decades of personal experience.)
• Myth: Gender and sex are either/or – you're either a boy or a girl; you can't be something in between.
  • Reality: Gender is multidimensional, and each dimension is a continuum. There are strong correlations between the dimensions, but many individuals clearly do not fit the pattern. Even on a physical level, some individuals have ambiguous genitalia, or chromosomes that do not match their (natural) appearance.
  • This is commonly known as the gender binary myth.
• Myth: Primary and secondary sexual characteristics are caused by genetics. XX chromosomes make you grow a female body and XY chromosomes make you grow a male body.
  • Reality: Actually, they're determined entirely by hormones – which, normally, are determined by what type(s) of gonads you have (ovaries or testes), which are normally determined by developmental factors while in utero which are mostly (again) hormones.
  • There are some hormonal effects which are hormonally reversible (switch to opposite hormones and it goes away), some which can be corrected surgically, and some which aren't fixable. See hormones for more details.