How many sexes are there

1. The biological anchor: gametes define the two-sex framework

In evolutionary biology and comparative studies the clearest, widely used definition of sex rests on gamete size—anisogamy—so that the functional reproductive roles map onto two sexes: the gamete-producing categories called male and female, a definition that underpins much contemporary biological literature ^{[2] [4]}.

2. Human development and the many ways biology can deviate from the binary

Human sexual development is influenced by chromosomes, gonads, hormones and gene networks, and medical literature documents a range of differences of sex development (DSD) and chromosomal variants that produce bodies not neatly classifiable as strictly “typical” male or female at birth, with intersex traits estimated in some surveys to occur at measurable rates in the population ^{[5] [3] [4]}.

3. Scientists who argue for “more than two” are often pointing to variation, not new reproductive roles

Some scholars and popular commentators argue there are more than two sexes because they enumerate intersex conditions or karyotype variants (for example historical proposals suggesting five or more sexes), but critics note these categories typically describe atypical developmental states rather than distinct reproductive classes equivalent to sperm‑producers versus egg‑producers ^{[6] [7] [8]}.

4. The case for a spectrum: mechanism-level complexity and intermediate cases

Recent biological work emphasizes that sex is multi‑dimensional—chromosomes, gene expression, gonadal structure, hormones and phenotype need not align—and that intermediate, mosaic or mosaicism cases expose the limits of a strict binary; proponents of a “spectrum” say these intermediate biological realities mean the two‑box model is overly simplistic ^{[1] [3]}.

5. Pushback: political, philosophical and ideological contests over definition

There is vigorous disagreement outside and within science: some conservative and religious commentators insist on two sexes only and treat intersex as abnormalities, while other critics accuse some proponents of expanding “sex” into political or cultural categories like gender identity; sources reflecting both poles appear in the reporting and explicitly advance social or ideological aims ^{[9] [10] [7]}.

6. What scientists and philosophers warn about conflating levels of analysis

Philosophers of biology and many researchers caution that conflating different biological levels—karyotype, gonads, gamete production, or social/legal categories—produces confusion; a careful taxonomy distinguishes reproductive categories (male/female), developmental anomalies (intersex/DSD), and social constructs (gender), and notes that assigning legal or social status based on simplified biological markers has real consequences ^{[2] [4] [1]}.

7. Practical takeaway: two reproductive sexes, many biological realities

For most biological and comparative purposes there are two sexes defined by gamete role—male and female—but human biology includes a range of intersex variations and mosaic conditions that complicate any attempt to map every individual neatly onto those categories; whether those variations count as additional “sexes” depends on the definition used, an explicit choice that the literature and public debate do not agree on ^{[2] [3] [8]}.

8. Limits of the reporting and unresolved questions

The supplied reporting documents scientific disagreement, philosophical analyses and ideological critiques but does not provide a single consensus statement that settles how many “sexes” must be counted under every possible definition; therefore any definitive numeral beyond acknowledging the binary reproductive roles plus documented variation would go beyond the sources provided ^{[1] [3]}.