BOF VI: The Chemist in me:

UPDATE: to address tormuse’s comments below.

This discussion came out of a comment I made about the usage of ‘cis’ to refer to people whose gender identity is more matching with their gender assigned at birth*.

I said:

“The chemist in me is glad that this word is being used in this way. :)”

And DM replied, asking about the ‘difference between Cis–trans isomerism and chirality’.

Not knowing if this was a serious question, and not wanting to derail a trans- issue conversation with chemical pedantry, I’m putting my answer in this blog post:

Don’t know if this is a serious question, but I’ll bite. Cis/Trans isomerism (generally) has to do with two Carbons connected by a double bond, with different things at R1/R2/R3/R4.:

R1     R3
  \   /
  /   \
R2     R4

R1     R4
  \   /
  /   \
R2     R3

These two molecules have the same chemical composition, but because the C=C bond is rigid and does not rotate, they can have different chemical properties.

Chirality is a little bit more difficult to explain using 2-D ASCII Art, but basically:


(With r4 at the back, behind the C, with R1/R2/R3 sticking out slightly from the page. #limitationsof2d)

Contrast with:


Which is a non-superimposable mirror image in 3-D. Even if R1/R2/R3 rotate around the r4 axis, they two molecules will never have exactly the same chemical characteristics (cf. Thalidomide)

*I’m sure I’m using some of these words incorrectly or imprecisely. Please comment to correct me!

3 thoughts on “BOF VI: The Chemist in me:

  1. As a fellow nerdy person, (or person with nerdy roots?) it also made me smile to learn of the use of “cis” by the trans community. 🙂

    I’m cis myself, but I’ve read up on trans terminology, so I feel reasonably knowledgeable enough to say that the phrase you used, “internal gender image” could be comfortably replaced with “gender identity.” As for the phrase, “birth sex,” it’s kind of frowned upon within the trans community; they prefer to use terms such as “gender assigned at birth,” based on the idea that gender is a social construct, rather than something one is inherently born with. Whatever your parents/doctors called you when you were a baby is the gender you were assigned at birth. People are typically either assigned male at birth (AMAB) or assigned female at birth. (AFAB)

    As for the stuff about chirality… I wonder if it could relate to nonbinary genders? (ie. genders outside of the gender binary of male/female) I’ve heard of a number of nonbinary genders, including intersex, (possessing body parts that traditionally belong to both males and females) genderfluid, (having a gender that changes from time to time) bigender, and agender. (There are probably others, but I can’t think of them right now)

    1. I sit corrected. 🙂

      As far as chirality, I could easily see people rotating through different ways of thought, or identity, with some easily accessible, while some are not. Or you could model it as superpositions of wave forms and have many more flexible options.

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