How is Gender and Sex a Spectrum

Gender and sex pervade almost every element of our lives. Every time we use a public restroom, go shopping or fill out a form, we are reminded that we must be male or female; man or woman; boys or girls.

What are gender and sex? Are gender and sex binary?

Gender refers to socially constructed roles, behaviours, expression and identities. It influences how people perceive themselves. Whereas sex is defined as a set of biological attributes like chromosomes, gene expression, hormone levels and function, and reproductive/sexual anatomy. These terms are distinct from one another and exist on their own spectrum.
Yes! Spectrum. Gender and sex cannot be constrained to a binary. They can be more accurately represented in the spectrum model (in which an individual’s sex, gender identity, gender expression and sexual and romantic orientations do not always exist as opposite endpoints). They can occur in any combination, and a person’s position on one spectrum does not always determine their position on the others.

Gender Spectrum: Gender is complex and it exists as a spectrum across all species. There are at least 10 medically accurate biological markers for assigning gender. These are:

1. Chromosomes: Different chromosomal expressions.
2. Gonads: Gamete producing organs (ovaries and testes).
3. Hormones: Types and levels of hormone secretion which vary across the sexes.
4. Secondary sexual characteristics: Features that appear during puberty and are not involved in reproduction.
5. External genitalia: Genitals visible outside the body.
6. Internal genitalia: Genitals present inside the body.
7. Skeletal structure: Sex differences may be seen in the pelvis, jaw done, brow and limb length and thickness.
8. Gene expression: Levels and different types of gene expression. DMRT1 (a dose sensitive transcription factor protein that regulates Sertoli cells and germ cells), SRY (an intronless sex-determining gene on the Y chromosome), FOXL2 (which has an important role in ovarian development and function) are a few of the genes that influence sex.
9. Brain Structure: Characteristics and activation patter of the brain differ by sex. There was an interesting study conducted by the European Society of Endocrinology researchers which involved studying brain activity and structure in transgender adolescents.
   The study led by Dr Julie Bakker involved MRI scans of 160 transgender children and teenagers diagnosed with gender dysphoria. The scans also used a method known as diffusion tensor imaging (DTI is an MRI based neuroimaging technique that makes it possible to estimate the location, orientation and anisotropy of the white matter tracts of the brain).

The study revealed that brain activity in transgender people resembled that of their gender identity more than their sex assigned at birth.
10. Personal identity: How a person identifies themselves. It is frequently the result of multiple factors interacting, making it a useful marker.

Sex Spectrum: It is a continuum of individuals extending from people with typical male physiology to those with typical female physiology.

1. Diversity observed in external genitalia:
   Genitals in humans vary greatly in shape and size. All the sex organs are derived from the same genital ridge, with testes being equivalent to labia and ovaries in women and the penis being equivalent to the clitoris. This is the reason why penis and vagina exist as a spectrum
2. Intersex people do exist:
   Individuals born with physical sex markers (genitals, hormones, gonads or chromosomes) that are neither definitively male nor female are classified as intersex. The existence of intersex people demonstrates that there are more than two sexes and that the distinctions between them can be blurred.
   A newborn having sex chromosomes XY or XX, may exhibit intersex traits.
   For example, when elevated levels of androgens are produced by either the foetus or mother’s adrenal glands, the XX chromosome child can be born with a phallus. In some cases, these newborns may appear to have a scrotum due to the fused labia.
   Similarly, an XY chromosome child can be born with an enzyme deficiency, such as 5-alpha reductase deficiency (a condition where male sexual development is affected before birth and during puberty, in most cases external genitalia appear female) and 17-beta dehydrogenase 3 deficiency (a condition where male sexual development is affected, in most cases external genitalia appear female). When this occurs, the "male" infant may be born without a penis and labelled "female" at birth.
   Currently, the intersex population ranges from 0.018% to 1.7% of the total population.
3. Sex Chromosomal Variations:
   Humans have a wide variety of chromosomes. Males, on average, have XY chromosomes, whereas females have XX chromosomes. Sex chromosomal variants are likely a result of one or both sex chromosomes being lost, damaged or added.
   Naturally occurring sex chromosomal variants in humans are as follows:
   • 45, X, Turner syndrome is a female-only condition that occurs when one of the X chromosomes is absent or partially missing. Turner syndrome occurs in about 1 in 4000 female live births worldwide.
   • 45, X/46, XY mosaicism is a rare mutation associated with mosaicism of the Y chromosome. Children with 45, X/46, XY mosaicism are frequently reported to have mixed gonadal dysgenesis (MGD), a variant form of Turner syndrome (TS).
   Other biological disorders can cause chromosomal and genital inconsistencies.
   Some individuals may be unable to express their gender identification in binary terms. They may, nevertheless, have a strong sense of gender even if they do not identify as a male or female. According to research , the concept of non-binary is based on the premise that gender identities exist on a spectrum rather than as binary oppositions Many cultures across the globe recognize the presence of a third gender. Example: Two-Spirited People for Native American/First Nations people, Hijra for South Asian people (also known as Kinnar or Kinner) and many more.
   Hence, sex and gender exist as a spectrum for humans and animals.