Biological sex is not binary

Biological sex is not binary is a family of arguments made in discussions and debates of the nature of sex as well as LGBT rights and revendications. The fallacious argument generally relies on definitional blurring, strawmanning. These arguments fail to address the steelman of the binary definition of sex, which is the ability to contribute a sperm cell or an egg cell to an act of reproduction.

Examples of definitional blurring (in which the definition of sex is blurred around indirect proxies of sex rather than the steelman)

• In a 2018 NYT piece, Anne Fausto-Sterling points to argue that there are, at birth, "five layers of sex," which are: chromosomal sex, fetal gonadal sex, hormonal sex, internal reproductive sex and external genital sex. Of course these are all just biological mechanisms which function to develop sexual capability, that is, the ultimate ability to produce a sperm or an egg as part of the act of sexual reproduction.

Examples of strawmanning

• In a 2020 blog post in Scientista, Darren Incorvaia claims that sex is not binary because some people are true hermaphrodites (i.e. they can produce both ovaries and testes). This, of course, misses the point of whether sex is binary in the steelman version of the argument. Even if someone was able to produce both sperm and egg, this would simply mean that they are the male of a given reproductive act and the female of another. Sex remains a binary as they could not have participated to either reproductive acts as anything else than a male or a female.