In sexually dimorphic mammalian species sex is most commonly by the ability to produce either the small or big gametes, not chromosomes.
In humans syndromes that lead to ambiguous (“intersex”) presentation and/or chromosomes are still operating in a binary system, eh Klinefelter affects boys.
The same is true for (very) rare hermaphroditism: in this case both gametes could in theory be produced, in practice though individuals are sterile.
In humans syndromes that lead to ambiguous (“intersex”) presentation and/or chromosomes are still operating in a binary system, eh Klinefelter affects boys.
The same is true for (very) rare hermaphroditism: in this case both gametes could in theory be produced, in practice though individuals are sterile.