The State of the Scientific “Debate”

Q: Is there a genuine controversy among biologists about the definition of sex?

A: If you’re looking at people studying the evolution of biological sex and sexual reproduction, there is overwhelming consensus. However, they’re insulated from cultural debates—just nerds studying computer models of how selection favored two different gamete types. It’s one of the most robust areas in evolutionary biology.

There are parallels to creationism. If you ask creationists about evolution, they’ll say it’s ‘hotly debated’ because they want to portray it that way. With sex, activist and online discourse began framing the issue as controversial. The controversy was spoken into existence, even though it’s baseless and incoherent.

No empirical findings have overturned the core biological framework. No Nobel Prizes have been given for discovering the supposed sex spectrum. Again, it was just spoken into existence.

What Would Change Your Mind?

Q: What evidence would you need to change your view that there are only two sexes?

A: That’s a crucial question. In the skeptic community, you always need to have something that could convince you you’re wrong. If you don’t, you’re just a zealot, not doing science.

For me, it’s really easy: we define sexes by the type of gamete an individual is biologically capable of producing. You’d need to present a third novel gamete type—in addition to or intermediate between sperm and ova—that an individual’s reproductive system could have the function to produce. That’s the only thing that could make there be more than two sexes.

Why There Are Exactly Two Sexes

Response to Wright’s (2025) “Why There Are Exactly Two Sexes”

Response to Mahr’s (2026) Response to Wright’s (2025) “Why There Are Exactly Two Sexes”