Dyadic or Perisex is a broad category that encompasses people who aren't intersex. Other common wordings are Endosex and Juxtasex.
Intersex individuals are born with biological sexual characteristics (such as gonads, reproductive organs, genitals, chromosomes, hormones, etc.) typically attributed to both sexes. Dyadic individuals, on the other hand, have only female or male sexual traits, and thus, they are assigned one of the two binary genders at birth.
Although Dyadic or Perisex individuals can identify with any gender identity, their biological sex is either female or male. This means that they were born with sexual traits that are allocated to one of the genders in the binary.
One's biological sex does not interfere with their gender identity, meaning that dyadic individuals can be transgender, queer, or have any identity within the non-binary umbrella. The dyadic term serves only to differentiate intersex individuals from non-intersex people.
All infants are medically assigned a sex, either upon prenatal sex discernment or at the moment of birth. Those who are not intersex are either Assigned Female at Birth (AFAB) or Assigned Male at Birth (AMAB), meaning that dyadic people can be split into these two groups.
AFAB - assigned female at birth - individuals typically possess XX chromosomes, have a female reproductive system (Fallopian tubes, ovaries, uterus, vagina), have external female organs (vulva), and upon reaching puberty, manifest higher levels of estrogen and develop female secondary characteristics (breast enlargement, increased pubic and facial hair, etc.).
AMAB - assigned male at birth - individuals typically possess XY chromosomes, have a male reproductive system (prostate gland, seminal vesicle, testis), have external male organs (penis), and upon reaching puberty, manifest higher levels of testosterone and develop male secondary characteristics (increased body hair, deep voice, muscle enlargement, etc.).
No. Although dyadic people are either AMAB or AFAB, one can be assigned a specific sex at birth and still fall into the intersex category.
The Dyadic concept was created by intersex people to describe non-intersex individuals without having to resort to words with potentially underlining meanings. This way, intersex wouldn't be the counterpart of normal or natural, for example, gaining a more appropriate connotation.
But is supporting new terminology really the way to fight the stigma against intersex individuals? The intersex community debates if reinforcing the existence of the gender binary is, after all, beneficial to their own situation.
On the other hand, many disagree over the right wording, not over the concept itself, hence the existence of different phrasings. The term endosex was officially used by many intersex organizations, but other intersex individuals still prefer the words dyadic or perisex.
The phrasing intrasex was also considered, but it was quickly discouraged and discontinued due to the similarity in phonetics and spelling with the word intersex.
Altersex / Alteradic / Transsex / Transexual / Transsexual - Individuals who are born dyadic but posteriorly alter their biological sexual characteristics through reassignment surgery and/or hormonal treatment.
Cisgender - Individuals whose gender identity coincides with their biological sex. Term created by the transgender community to refer to those who are not transgender.