My work deals with transformations in matter, wherein one physical form (a 'phase') changes to another. The initial form has often traditionally been called the 'parent phase' and the transformed form has been called the 'daughter phase'. I think this borrows from nuclear physics, where a 'parent' nucleus transmutes into a 'daughter' nucleus; which may further transmute, becoming a 'parent' in turn.

Off late, it has been pointed out (in private conversation) that 'parent-daughter' is not in the spirit of inclusive language. I'm taking this at face value, and would like suitable alternatives.

**It has been pointed out that criticism of this premise should be allowed space- I welcome this too, though the primary interest is in alternative terminology.

**Several commenters have suggested replacing 'daughter' with the gender-neutral 'child'. This is already a great improvement, but there could be another apprehension; the 'parent' and 'child' often don't co-exist, since one replaces the other (to various degrees). It is not uncommon to describe the transformation as one phase 'consuming' the other. I speculate that this aspect may lead to some discomfort (it should apply equally to nuclides then). This caveat somewhat distinguishes this case from data structures example, where the child (class for eg.) inherits from the parent, but both continue to exist.

'Precursor-product' is one possibility, but this (possibly) carries different connotations in chemistry (in my limited understanding, precursors are secondary to the product in value terms- although this could be my ignorance). 'Pre-transformation' /'post-transformation' could work, but they sound clumsy. 'Initial/final' is not accurate nor properly descriptive. 'Phase 1/Phase 2' could also work, but they are tedious because the reader has to refer to what 1 and 2 mean.

Are there any suitable alternatives, either new, or existing elsewhere that could fit the requirement?

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    Is the issue with the "daughter" part of the phrasing (as it isn't a genderless expression) or with the whole phrase? because if it is the former, something along the lines of parent-offspring might solve the problem.
    – Sursula
    Commented Dec 14, 2022 at 9:56
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    I’m taking this at face value. You’re asking everyone here not to challenge your premise that “inclusive language” means science needs to be dehumanized as much as possible and cleansed of any terms that “you speculate may cause discomfort” to someone, without any objectively justifiable reason. But if no one challenges that premise, we’ll be left with a permanent webpage that reinforces those flawed beliefs and causes even more people to adopt them (or to cower in fear that others have adopted them). So, I think it’s unreasonable to expect others not to challenge your premise.
    – Dan Romik
    Commented Dec 14, 2022 at 16:53
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    @AppliedAcademic could you ask your colleagues what they mean by it not being inclusive? It might be only the gendered aspect, and "parent-child" would be fully acceptable.
    – Drake P
    Commented Dec 14, 2022 at 18:06
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    @DrakeP Most style guides (AP, Chicago, etc) recommend against using English feminine names/pronouns to describe inanimate objects as has traditionally been done for, e.g., ships at sea. Arguments include that this is akin to treating women as objects/property or that these are feminine names given affectionately by men, and upholding this tradition implies that men (and not women) are the ones that get to name these things.
    – Bryan Krause
    Commented Dec 14, 2022 at 19:41
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    @BryanKrause I know this and recognize why "parent-daughter" is not preferred; I was questioning whether "parent-child" is actually insufficient like the OP is concerned about, or if it would be satisfactory to their colleagues.
    – Drake P
    Commented Dec 15, 2022 at 16:27

11 Answers 11


How about "parent" and "child"? By keeping "parent", you are maintaining continuity with the terminology that others are familiar with, which is generally good for scientific communication. By using "child", the relationship is equally clear as "daughter". For those who are not familiar with the parent-daughter convention, parent-child is equally clear. For those who are used to parent-daughter, then it will be fairly clear that you are being explicitly gender-neutral without a significant change in meaning.

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    @AppliedAcademic, I still think the principle of maintaining continuity with established terminology is very important. To invent a new term is completely different from adjusting established terminology. If you were inventing the term yourself, you would have the liberty to use the best terminology you like. But if established terminology already exists, then you should avoid radical changes (in this case, departing from the parent metaphor) except for very good reason; otherwise, you risk confusing readers into thinking that you are talking about something else.
    – Tripartio
    Commented Dec 14, 2022 at 19:17
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    @AppliedAcademic Gender stereotyping and all the baggage that goes with it is something we deal with day to day every day, but parental cannibalism is a thankfully vanishingly rare concern. I am not surprised to hear that some may take objection to the unnecessary use of a gendered term in this context, but I would be genuinely surprised if anyone were concerned about the implication of children replacing parents (in fact, I am surprised it has occurred to you in the first place).
    – Carcer
    Commented Dec 14, 2022 at 19:39
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    @Carcer "parental cannibalism" - Call them saturn and son molecules? Commented Dec 15, 2022 at 3:32
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    The good thing about this also is that you're not just making up something completely new. Parent-child is pretty common terminology in computer science when talking about the relationship between two objects; so, the fact that this is already the preferred way of expressing relationships in other STEM fields should help with adoption.
    – Nosajimiki
    Commented Dec 15, 2022 at 21:23
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    @AppliedAcademic Asking us for better words than parent/child is doomed to failure, since you have not told us what these words describe in the first place.
    – Daron
    Commented Dec 15, 2022 at 21:46

Sorry. I'm sensitive about such things and inclusivity has high value for me, but I don't see any issue in the "traditional" terms. They aren't pejorative. They aren't intended to be sexist. They don't exclude. They don't refer in any way to humans. It is just a metaphor and already well understood.

I see no issue with using "child", though it is a biological metaphor for something non-biological, just as "daughter" is. "Derived" might be accurate if you think you really need to be (and seem) "politically correct".

Using non-traditional terms in new papers should have a high bar for acceptance, since they can confuse people. The old papers on which a field is built suddenly become either less understandable or "suspect". It isn't my field, so not my place to set that bar, but it should be a consideration.

I'll note, for the record that it was progressives/liberals in my daughter's generation, many at women's colleges, that initiated the term "politically correct" for such overly "sensitive" thinking among their own peers. Yes, they understood sexism pretty clearly, but also understood that some things are just ... searching for a non-offensive word here and not coming up with it. Maybe "childish" works.

What does "inclusivity" even mean for transformations of matter?

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – cag51
    Commented Dec 16, 2022 at 13:52
  • -1 for several things really. OP didn't at say given phrase was pejorative or sexist, which appear to be projections / straw men. OP just said it was "not in the spirit of inclusive language" (which while not the most precise language seems to just be a reference to the recent tendency to avoid gendered language). OP is not referencing using terms in a paper. The comment about political correctness seems completely off-topic. Commented Dec 20, 2022 at 18:17

Frame challenge: There is nothing "non-inclusive" about using the word daughter as a metaphor.

Your assumption that the "daughter" terminology is non-inclusive is grounded in an apparent belief that using any gendered word in a metaphorical context is "non-inclusive" to people whose gender was not referenced. This belief reminds me of a joke about a mother who gave a present of two ties to her son-in-law. On his next visit he wore one of them, thinking that would please her. Offended, she asked “What, you don’t like the other one?”

More seriously, I see several problems with this tendency to automatically classify as "non-inclusive" any non-literal mention of some but not all genders. First, you are ignoring the fact that many languages, collectively spoken by billions of people around the world, assign a gender to all nouns. (It may very well be the case that the use of "daughter" in the scientific context you are asking about can be traced back to one of those languages, see below.) Thus, this particular notion of non-inclusiveness strikes me as being very Anglocentric, to an extent that could even reasonably be perceived as offensive by speakers of some of those other languages.

Second, I find it problematic that the belief that something is non-inclusive cannot be argued with, since if you disagree, then by the self-reinforcing beliefs of some of the people who promote these kinds of concepts, you are by definition "against inclusion", a sexist, bigot, etc. Who wants to risk being labeled with such terms? In other words, some of the beliefs around "inclusive language" strike me as being part of "a closed system of logic" (a term that I believe was originally used as part of a set of criteria for recognizing cults, see here). When I see self-justifying logic of this type, I am immediately put on my guard, and would like to ask: forget vague terms like "non-inclusive" that anyone can define in a way that suits their preferred narrative; please explain, what exactly makes this particular use of language bad?

Third, let's consider the specific term "daughter" you are asking about. You've stated that the use of this term in the scientific context of your research area originates in terms like "daughter nucleus" in nuclear physics. The historical origin of that term is discussed here. Meitner and Frisch, the two discoverers of nuclear fission who apparently introduced the "daughter" terminology, were both Austrian-born scientists (i.e., speakers of a language with gendered nouns). You could say they were an "inclusive" team -- one of them was a woman, the other a man. Moreover, it looks like they borrowed their terms from an earlier accepted terminology in biology of referring to cells produced by other cells as "daughter cells" (with the original cell being termed the "mother cell"). That terminology, which is discussed here, seems pretty logical, as it is actually based on a scientifically reasonable metaphor that only "female" things can produce their own offspring.

Given this more historically informed way of looking at things, is it still tenable to argue that "daughter phase" is non-inclusive? It seems to me that if you still support this premise, in order to be consistent you would also have to deem the etymologically related uses of "daughter nucleus" in nuclear physics and "daughter/mother cell" in biology as problematic and in need of complete overhaul. So basically you'd be rejecting much of the accepted terminology of multiple areas of science (as well as the German language, French, Spanish, etc). Well, perhaps some people would hold such extreme positions. But in my opinion, this way lies nothing but madness.

Summary: we should seek to be inclusive wherever possible, sure. But this issue simply isn't an example where that principle has any relevance.

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – cag51
    Commented Dec 16, 2022 at 4:46

As @wimi already commented, there is a simple replacement, use the "parent and child" analogy as it is used in the programming world, instead of the "parent and daughter".

Regarding the issue that:

"the 'parent' and 'child' often don't co-exist"

It was already an issue intrinsic in the 'parent' and 'daughter'. As Abrahm Lincoln once said in his blog, make things as simple as possible, but not simpler.

If the parent and child analogy does not work, use initial phase and final phase, or whatever word will work (if you feel describing phase 1 and phase 2 as a burden).


As a software engineer, I found myself in need of this metaphor many times when describing data structures and state transitions. I always used "parent" and "child", not because I didn't want to offend anyone, but because if I used "mother" and "daughter" some of my readers might wonder if I was planning to use "father" and "son" for some other relationship, and holding "parent" and "child" in reserve for the more general case.

Software engineers tend to overthink everything. However we needed to be careful and precise with language because from c. 1956 to c. 1984 there was very little common idiom in software. Most of these data structures and state transitions were being described for the first time.

  • Thanks, this is another useful justification for parent/child. Commented Dec 15, 2022 at 3:57

For situations in which I wanted to discuss the transformation of a particle or system from a "parent" (the word I used) state into multiple subsequent states, which were potentially quite different in character, I used (instead of "daughter") the word "progeny." You might find that useful.


A lot of good suggestions already, here is a simple terminology from chemistry:

educt - product

The educt is a material before a chemical reaction, the product what comes out of it. This seems to hit the nail of what your first paragraph describes. It is short and devoid of biological connotation.

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    Very nice, I didn't know this term. Thank you! Commented Dec 16, 2022 at 17:12
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    Given that, if anything, the purpose of using a metaphor is to make the concept more comprehensible, it should be noted that the new metaphor suggested here would hinge on the reader's familiarity with the term "educt". Commented Dec 17, 2022 at 21:23

Root/Trunk, Branch, Leaf

Using a tree analogy takes away any connection to parents and children, etc. You'd use "Root" (or possibly "Trunk") to refer to the oldest ancestor. Any children of the root are "Branches", which may have their own Branches, etc. Children without any Branches are called "Leaves".

This terminology is often used in computer data structures, but can be applied in other circumstances as well. One thing it also gets around is the issue that the "Parent/Child" analogy is somewhat inaccurate, in that in reality, a child has not 1 but 2 parents (assuming normal sexual reproduction as opposed to mitosis or something), so the analogy breaks down when you consider that. (Yes, a tree has multiple branching roots as well, but we generally restrict the analogy to the part of the tree that's above ground.)

Only problem with this is applying to the original example of atomic nuclei, as it implies that the elements are all still connected to each other as they would be on an actual tree, but without knowing what specific case you're talking about it's hard to say whether this would be a good or bad thing.

  • One issue of this alternative metaphor is that it may not be immediately obvious whether roots, branches, and leaves are inherently different or just structurally different. For instance, if a tree consists of just one node, that single node is a root and a leaf at the same time. If a leaf gains a new child, that new child is a leaf, and the previous leaf has transformed into a branch. Depending on prior knowledge of the readers, this can be confusing, and possibly more so than the parent/child metaphor (but it depends very much on what is trying to be conveyed). Commented Dec 17, 2022 at 21:28
  • @O.R.Mapper Yeah, in all fairness every analogy breaks down on some level. Without knowing the OP's specific use-case it's hard to say which model best fits it, just figured I'd point out another way of looking at it. Commented Dec 21, 2022 at 14:36

Might "parent"/"offspring" avoid the negative connotations of "child"?

Otherwise, I have a vague feeling that "parent"/"daughter" is used for asexual reproduction, which seems to be the best metaphor here.


The initial form has often traditionally been called the 'parent phase' and the transformed form has been called the 'daughter phase'.

In my experience, this is not true. Phases of matter are traditionally given much less helpful names. Some examples are:

  • Phases of water ice are named with Roman numerals
  • Phases of certain crystals are named with lower case Greek letters
  • Crystal phases are named according to space group symbols, for which there are nine different conventions listed in Wikipedia

They are also names like solid, liquid, supercritical, glass, etc.

"parent/daughter" is rather non-specific, and in my experience, non-traditional. It would be better to use one of the more traditional names.

  • This is outside of my own field of expertise, but a quick literature search shows that "parent/daughter phase" are indeed being used, e.g. in crystallography. So I wouldn't just dismiss these as non-traditional.
    – Emil
    Commented Dec 17, 2022 at 10:45

How about any of the following pairs?

  • input, output
  • source, destination
  • initial, final
  • previous, next
  • old, new

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