Building a sex is harder than most people imagine

Now will you believe me? I keep saying that sex and sex determination are far more complex than just whether you have the right chromosomes or the right hormones or the right gonads, and now here’s a lovely diagram that illustrates some of the steps in sex determination.

The biology is set up to favor driving an individual to one side or the other, but there are so many detours that can be taken en route that it is ridiculous to ignore all the people who end up following a more unique path.


  1. weylguy says

    Science, schmience. It’s so much easier to adopt the notion that, according to the Apostle Paul, if you’re LGBT you’re going to burn in hell forever.

  2. blf says

    Re @2: I thought that was “the notion that […] if you’re someone we don’t like you’re going to burn in hell forever”, retrospectively applied and with an unclear & varying definition of who the “we” who decides are.

  3. katiemarshall says

    This is super cool and I would love to use it in my classes. But it seems pretty low res. Any idea where the original is from?

  4. imaginggeek says

    I like that the pink side is the male side…how long until someone comes along to complain that the diagram somehow denigrates traditional maleness or some such claptrap.

  5. latrans says

    Katiemarshall, PZ linked to the article (clickable text below the pic). It has an enlargeable image – though it still makes for small text on a busy ppt slide.

  6. Jado says

    This is BS – the Bible says that God made Man and Woman. Are you saying God lied? Cause God doesn’t lie – the Bible says so.

  7. Reginald Selkirk says

    … a more unique path

    Unique means one of a kind. How can something be more one of a kind?

  8. robro says

    Selkirk — From my desktop dictionary (New Oxford American Dictionary), “…since the core meaning of unique (from Latin ‘one’) is ‘being only one of its kind,’ it is logically impossible, the argument goes, to submodify it: it either is ‘unique’ or it is not, and there are no stages in between. In practice, the situation in the language is more complex than this. Words like unique have a core sense, but they often also have a secondary, less precise (nonabsolute) sense of ‘very remarkable or unusual,’ as in a really unique opportunity. It is advisable, however, to use unique in this sense sparingly and not to modify it with very, quite, really, etc.”

  9. timmyson says

    I knew there were a bunch of ways to get non-binary sex, but wow it’s cool to see them in one diagram like this. You say “some of the steps”, how complete a representation of known non-binary paths this represents?

    I would *love* to see populations represented in these paths. Each of these less common paths is going to have a pretty small population, but I’ll bet it’s a sizeable minority.

  10. Holms says

    This is why I have always found the word ‘spectrum’ a tad unsuitable for sex. It brings to mind the visible light spectrum – a rainbow – wherein all colour bands have the same width as each other. Yet if you used a rainbow to represent the relative populations of the various non-binary sexes, almost the entire width would be taken up by the two colours representing male and female, and the rest would be crammed into less than 1% of the total. I guess it would look like a band of red and violet, with a blurry / colourful border taking up a sliver in the middle.

  11. se habla espol says

    @Jado, #9: Read your Wholly Babble some more: it says “male and female created he them”. In other words, Adam and Eve, according to the WB, were fully intersex.