As I'm not in school today, I feel like giving a little chemistry lesson 😆
Cis and trans are terms used in organic chemistry, to differentiate between two different forms of the same chemical.
These chemicals are called isomers, and they have the same chemical formula (the same number and type of each atom). If you just looked at their chemical formula, you might think that they are exactly the same.
For example, CHF=CHF.
However, carbon requires 4 bonds to be chemically stable, and in this example, each carbon only has access to a H, a F and another C.
So, each carbon here makes a double bond to the other carbon. It looks like an equal sign.
This is significant, because a double bond does not allow for rotation around itself.
If there was only single bond, the groups on the end could rotate, and you could change from having F and H on the top of the molecule, to having H and H, or F and F on the top.
If there is a double bond, the groups are locked in that orientation.
Simply, if two of the same groups are locked on the same side of the double bond, that isomer is "cis"
If the same groups are locked on opposite sides of the double bond, the isomer is "trans".
This can have a massive effect, for example one isomer of paracetamol is inactive in the body (but harmless), whilst the other version has it's analgesic properties.
Now, students are also taught to use the E/Z classification for isomers, as well as cis/trans (same/across)
E stands for Entgegen (German = opposite)
Z stands for Zusammen (German = together)
I'd be quite up for calling us zusammen women!
Can't think why entgegen women isn't used!?
But ultimately, cis is a chemical term. A geometric double bond is either cis or trans.
Given that there are meant to be over 100 different genders, transgender REALLY doesn't make sense.
Perhaps we should go back to using transsexual?
Although, that phrase was knowingly replaced, as talking about transsexual children starts to raise all sorts of questions.
Transsexual adults, and gender questioning children.