Some people are intersex (typically this means they have ambiguous genitalia or internal sex organs). Therefore, there are people who are neither entirely male or female biologically. You can have an XY person who outwardly has female genitals, but has internal testicles (Androgen insensitivity syndrome)

There is also some question whether some things we don't consider intersex are actually a form of intersex, such as homosexuality. A lot points to homosexuality being innate, not learned, and I personally think this points to it being a form of intersex that affects the brain, not the genitals.

Some disorders can cause both. For example, females with Congenital adrenal hyperplasia (CAH) can have ambiguous genitals and also are more likely to be lesbian.

> I also wonder why Edith felt the need to mention gender not being binary in a discussion partly about whether biological sex influences choice of job, considering the fact that as far as I know biological sex is indeed binary, you either have at least one Y chromosome or you don't.

I think she refers that gender is not binary as you can be straight male, straight female, gay male, gay female, bisexual, asexual, etc.

I am not completely sure but I think there can be mutations where you have 2 chromosomes X and 1 Y. So XXY [1]

[1] https://en.wikipedia.org/wiki/Klinefelter_syndrome

Sex, sexual orientation, and gender are different things. By gender spectrum she means that most people's behavior is somewhere along a continuum between completely masculine and completely feminine and that virtually nobody is at one extreme or the other.

I think the point she's making is that while men and women have different interests as groups, there are plenty of women who are interested in what are perceived as masculine things (in this case probably computer programming) and vice versa.

By gender, she's referring to gender identity which is certainly not binary. There is a pretty high correlation between someone's chromosomes, "equipment", and gender identity but it's not 100% and any of those can vary on a spectrum.

I've been doing some reading on transgender individuals, and the current knowledge is that gender identity has some kind of durable biological basis, we just don't know quite what it is yet. It's not simply a delusion and a refusal to accept your "real biological gender" based on your chromosomes, etc. Some people don't identify as either gender.

And like the other poster mentioned, there are genetic outliers like XXY chromosomes (intersex), and other things that can happen such as Androgen Insensitivity Syndrome (XY females due to lack of response to testosterone).

Don't get me wrong, I accepted gender not being binary, I just wondered how that was relevant to the discussion.

I did not know about AIS, really interesting stuff.