So what/if/mammals cannot change sex

Irrelevant Comment: “Mammals cannot change their sex.”

Usage

the lone comment on an article about animals that naturally change sex, observing that none of them are mammals (presumably in support of the idea that Humans cannot change sex)

This point is typically raised in "gender critical" (GC) arguments against transgendrity. The sequence tends to go like this (TA = trans advocate):

• GC: Biological sex is immutable, so trans women are just men in dresses.
  • TA: But there are several species of animal which change their sex as part of their natural life-cycle.
    • GC: None of those are mammals. (Implied: humans are mammals, therefore this doesn't prove anything about humans, so humans still cannot change sex.

Example

“

First, this article only proves that there are two genders, male and female. It also proves that some species can “naturally” change their gender as necessary for survival of the species. So, please let me know when the first human “Naturally” changes their gender simply by willing it and without surgical or hormonal intervention. When this happens I will only further prove that there are two genders. When a human being can naturally change into something other than a male or female with a completely different set of reproductive anatomical parts and then successfully reproduce you will finally have shown that humans are in fact non-binary. Until this happens saying you are non-binary is simply a mental illness or a severe lack of education.
”

—2016-07-16 10 Sex-Changing Animals That Don’t Adhere To Gender Roles: "Gender absolutely exists on a spectrum -- and these animals prove it."

Comment claims:

• Claim: This article proves that there are two genders, male and female.
  • Uh, no, it doesn't prove that; it doesn't even talk about the idea of other genders. Omission is not proof of nonexistence.
  • The fact that an organism can change from one sex to another, however, does mean that it will spend some time in an ambiguous gender.
• Claim: some species can “naturally” change their gender as necessary for survival of the species. Implied: only "natural" change, "simply by willing it", is real change. appeal to nature (If someone is cured of a disease by modern medicine, are they not "really" cured?)
• Statement: "When a human being can naturally change into something other than a male or female with a completely different set of reproductive anatomical parts and then successfully reproduce you will finally have shown that humans are in fact non-binary."
  • This implies an additional requirement for "changing sex": the end result must be fertile in the target reproductive role. This is another example about how gender-critical proponentsists see gender as being entirely about reproduction, which it is not.
    • Consider: If someone is born infertile, does that mean they don't have a gender?

Analysis

Although most GC proponentsists will now skip directly to the hardened form ("humans cannot..."), effectively moving the goalposts, the claims that biological sex is immutable and that changing sex is unnatural will still sometimes be stated, in spite of being refuted by the existence of these animals. intellectual dishonesty

This also illustrates that biology does not inextricably link gender and genetics.