Similar to "dimorphic" but specifically about difference between the human biological sexes.

These are some ____ facts: men have higher testosterone than women, women have better colour vision than men.

I've been considering adjectives starting in hetero- but haven't found a suitable one yet.

  • 3
    What makes you think there is one? Sexual difference is good enough. Here are some facts about sexual differences. Since there are only physically two in this sense.
    – Lambie
    Commented Nov 22, 2021 at 21:25
  • There's a Wikipedia article titled sexual dimorphism, which seems not to be strictly about shape. On searching, you can run across sex-dimorphism. If you drop facts, you could say sexual dimorphisms. Commented Nov 22, 2021 at 22:04
  • @YosefBaskin — A chemist might regard blood testosterone concentration as physical, in so far as it can be measured, but this hardly conforms to the general English usage of the word.
    – David
    Commented Nov 22, 2021 at 23:14
  • 1
    Why do you need the word "facts" What is wrong with "Here are some gender differences."? And, by the way, are you talking about birth gender, identity gender, biological gender, or legal gender?
    – Tuffy
    Commented Nov 23, 2021 at 0:53
  • 2
    @Tuffy — He is talking about sex, not gender. I would be thought rude if we made gratuitous remarks about sex if you asked a question about gender. The fact that you may dislike his example sentence does not excuse you of similar rudeness. It is obvious from the use of the words "sex", "biology" and "testosterone" that he is referring to human XY males and XX females. (I'm not sure he is right about colour vision. There is a difference in the incidence of red-green colour blindness, but that is on a per-individual basis.)
    – David
    Commented Nov 23, 2021 at 13:00

3 Answers 3


I wouldn’t use it in the space in the sample sentence because I find that poor, but to make it quite clear, when discussing sex differences biological scientists use the term:

sexual dimorphism

whether or not there is physical shape involved. This extract from the entry in Wikipedia reflects general contemporary scientific usage:

Sexual dimorphism is the condition where the sexes of the same species exhibit different characteristics, particularly characteristics not directly involved in reproduction

(I provide further evidence in an appendix, as this view has been contested.)

In a modified sentence similar to that in the question I might write:

These are some facts regarding human sexual dimorphism…

as I regard something like ”sexual-dimorphism facts” unspeakably ugly. However, in this case I would be more intelligible to a general audience writing:

These are some specific facts regarding (non-reproductive) differences between the sexes…

So, as often in questions on this list, I do not accept the structural straight jacket the poster wishes to force himself — and others — into.

Appendix: Examples of current usage of sexual dimorphism

It has been asserted that the term sexual dimorphism only refers to difference in physical characteristics, or to these and observable behaviour, but not to the concentration (loosely referred to as ‘level’) of blood constituents such as testosterone. I accept that this scientific term was originally coined and used in such a restricted sense (the term dimorphism dates from 1832) , but this restriction was quite natural as the term was introduced when biology was restricted to physical observations. As techniques for analysing biological features other than by physical observation, the term was applied to differences in such features. Like it or not, this is the contemporary usage in staid academic journals.

I start with a recent example I think pertinent because it refers to a human hormone and appears repeatedly when one searches the literature. However it has the advantage over testosterone that it is not a sex-specific hormone. It is insulin, a hormone produced in the pancreas that regulates the uptake of glucose from the blood, and the absence of which is the cause of type I diabetes. Here is an example:

The term is also used in relation to other constituents of blood, such as lipids:

and to cellular constituents of blood, such as cells of the immune system:

And as a parting shot, the geneticists’ favourite, the fruit fly Drosophila melanogaster, provides a feast in the sexual dimorphism of odorant molecules and their receptors in the brain, as evidenced by the title of this article:

  • Sexual dimorphism is visible differences in characteristics or behavior between sexes, not testosterone levels.
    – DjinTonic
    Commented Nov 22, 2021 at 23:28
  • 1
    @DjinTonic — saying so does not make it so. What is the authority for your statement? I understand the derivation of the word, dimorphic, just as I know the derivation of the word, homophobic (for example), but in both cases we are talking about contemporary English usage, not Greek literature. I will provide evidence for contemporary English usage in an Appendix to my answer.
    – David
    Commented Nov 23, 2021 at 12:02
  • "Sexual dimorphism Zoology Distinct difference in size or appearance between the sexes of an animal in addition to difference between the sexual organs themselves." Lexico
    – DjinTonic
    Commented Nov 23, 2021 at 12:22
  • "Sexual dimorphism, the differences in appearance between males and females of the same species, such as in colour, shape, size, and structure, that are caused by the inheritance of one or the other sexual pattern in the genetic material." Britannica
    – DjinTonic
    Commented Nov 23, 2021 at 12:23
  • 1
    @DjinTonic — You might have waited. And my examples are just a few of literally hundreds you can find on Google Scholar or doing a PubMed search. Usage, usage, usage.
    – David
    Commented Nov 23, 2021 at 12:50

"Sex differences."

To be more specific, if you mean chromosomal sex, then you can refer to it as an allosomal or gonosomal difference. From Wikipedia:

A sex chromosome (also referred to as an allosome, heterotypical chromosome, gonosome, or heterochromosome, or idiochromosome)...

Of the two statements you present, only "women have better colour vision than men" is ultimately an allosomal difference because your average color blindness is a recessive sex-linked trait. The statement "men have higher testosterone than women" cannot exactly be linked to sex because of various factors such as hormone replacement therapy and hormonal conditions.


You can use "gender facts".




  • 1
    Note, "gender" and "sex" are not synonyms. Most of the books shown are in the so-called "soft sciences," or even the non-science of business strategy. The OP never said they had to stay within a scientific use case, but they did choose the word "sex." Commented Nov 22, 2021 at 22:09
  • @AndyBonner "Gender" refers to the fact of being male or female according to OALD; this dictionary lists specifically "sex" as a synonym of "gender": wordhippo.com/what-is/another-word-for/gender.html. It seems to me that "gender" is very close.
    – LPH
    Commented Nov 22, 2021 at 22:14
  • I can't find proof gender is a well-understood adjective
    – minseong
    Commented Nov 22, 2021 at 23:18
  • It is not an adjective; however in the compounding with "fact" ("gender fact" is a compound noun), it acts as an adjective.
    – LPH
    Commented Nov 22, 2021 at 23:37

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