There are two sexes, male and female, because there are only two types of gametes, sperm and eggs. There are no “speggs.” Zach Elliot narrates this short video, useful for those who slept through 7th grade biology. References and transcript here.

Added April 8, 2023:

Citations here. 

[Supp Dec 10 2024]

[Supp Jan 13, 2025]

Biologist Colin Wright explains in this second short video that sex is real, immutable and binary:

[Supp Jan 15, 2025]

From Billboard Chris:

The word ‘gender’ has been corrupted by a worldwide cult to mean gender identity — a magical inner feeling of being male or female, based on regressive stereotypes.

We should no longer use that word.

There are two sexes, zero genders, and infinite personalities.