In a comment on my post Gender in French, Pat Franczyk shows the danger of confusing the meanings of these two words.

It has often been said that “language has gender, but animals and plants have sex”. The ambiguity of the second half of this aphorism shows why gender is often used to mean ’sex’. The OED gives examples as early as 1387 of gender in which the meaning is obviously ’sex’ , but to my eyes, most if not all of the examples can be interpreted as being ironic, and the first edition says that this meaning is ‘now only jocular’ (published October 1898).

In the course of the 20th century, gender came more and more to mean ’sex’ in the sense of the biological assignment to either male or female, probably because sex was being increasingly seen solely as what the Longman Dictionary of Contemporary English defines as “the physical activity that two people do together in order to produce babies”, leading to the joke answer to the question on a form requesting personal information: “Sex? – Yes, please!” rather than “Sex? – (fe)male”.

If the biological sex of a creature is determined by the nature of its chromosomes, then the definition of gender reassignment given in the latest (7th) edition of the Oxford Advanced Learner’s dictionary is nonsensical: “the act of changing a person’s sex by a medical operation in which parts of their body are changed so that they become like a person of the opposite sex”. No operation can yet change a person’s chromosomes, so although the second part of the definition is correct – ‘they become like a person of the opposite sex’, the first part: ‘changing a person’s sex’ is incorrect.

To return to Pat’s comment: the way in which gender is used in grammatical descriptions of language has nothing to do with sex. The observation of linguists over many centuries is that a large number of nouns sharing the same characteristics (in Latin, for instance, the same endings in the various cases) happen to refer to male creatures. It was therefore convenient to call that class ‘masculine’. Likewise for a large number of other nouns, referring to female creatures, to call that class ‘feminine’. The Latin name for a class was genus, whose plural was genera. It is from this word that we derive ‘gender’ (via French genre). In other languages, the genders may have nothing at all to do with the sex of the class members – size, shape, number may all be categories that form a gender.

Pat is misunderstanding this, and interpreting ‘gender’ to mean exactly the same as ’sex’. It would have been better if the two words could have been kept apart. Gender has been used by sociologists to refer to the cultural assignment of individuals separately from their sex – such as the Indian hijras – and I have no problem with this: it is a technical term, as it is in linguistics. Unfortunately, the English language has confused the two words, and so made it that much harder for linguists to spread knowledge of how language really works .