Hi all, friendly neighborhood biologist here again. Going to repost this thread as a reminder that the science of human sex is incredibly complex. We the people must understand this complexity if we are to create a more perfect, just, and equitable union. https://twitter.com/RebeccaRHelm/status/1207834357639139328

The modern concept of gender as an identity within the English language wasn't established until the 1950s, but has been present in many non-western cultures for centuries...

...we owe the rise of gender as a concept within English to the many named and unnamed intersexed people who were subject to, in some cases, profoundly cruel scientific studies...

...which established that one's sense of gender identity (or lack thereof) can be independent of a person's biology...

In other words, the study of variation in human biological sex was used to inform our modern understanding of gender. But biologists do not study gender, and there are flaws with claiming that science "proves" there are only two genders:

1) Gender is a form of self-awareness that is not limited to any binary measure. It is a subjective experience. We are each our own absolute authority on this topic. The tragic story of David Reimer is evidence of this.

2) Variation in human biological sex exists, and failing to recognize this variation can lead to profound abuse.

Our ideas of the world change as we learn more about the world itself...

We used to think biological sex was simple, 'XX or XY'. We now know it's vastly more complex. And the experience of trans-individuals in informing this understanding...

It is profoundly remarkable that human cells can change based on the presence of absence of certain hormones, even in adults. Should a trans woman with breasts and high estrogen levels be denied a mamogram because her chromosomes are XY?? Is that fiar? Is that justice?...

Trying to find a "one size fits all" legal definition of sex will discriminate against people both socially and medically and isn't an accurate reflection of our best science...

Biological sex is complex. Sex is not gender. Gender is a spectrum. The world is complicated. Kindness and respect don’t have to be.

p.s. because we're all in different parts of the world with different politics: Here's what's happening in the US. Some politicians are trying to redefine legal sex. Some propose using chromosomes. Yesterday one politician posted a sign. It is not a good sign.