HWN Suggests

Beyond X & Y: Chromosomes and Sex Organs

Sex and gender are complex, and our understanding of both is constantly evolving. Even a quality as seemingly simple and binary as biological sex is a spectrum rather than an either/or. In fact, sex chromosomes — and how those chromosomes translate into physical features — can vary in quite a few ways. Here’s what’s regarded as the “norm”: XY chromosomes = penis & testes = man XX chromosomes = vagina & ovaries = woman. Gender is subjective to each person, and sex organs don’t dictate gender. People with penises aren’t necessarily men, and people with vaginas aren’t necessarily women. The thing is, XX and XY chromosomes aren’t cut and dry, either. Actually, sex chromosomes and genetic expression…

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Articles of Interest

Clergy Corner: Are you XX or XY?

Although the words gender and sex are often used interchangeably, they have different connotations; sex tends to refer to biological differences, while gender more often refers to cultural and social differences and sometimes encompasses a broader range of identities than the binary of male and female.”

Human Sex Chromosomes Are Sloppy DNA Swappers

The genetic bundles that code for males and females can get a little messy when they trade pieces during cell division.

Nettie Stevens discovered XY sex chromosomes. She didn't get credit because she had two X’s

Before Stevens, we were utterly clueless about how embryos become boys or girls. Thanks to Stevens’s work — and the work that built upon it — we now know that sex is hereditary, and that dads’ sperm in particular determine the sex of offspring.

One in 500 men carry extra sex chromosome, research suggests

While most men have one X and one Y chromosome, some are born XXY or XYY, putting them at increased risk of health issues ranging from type 2 diabetes, blocked blood vessels and chronic obstructive pulmonary disease (COPD), a lung condition, the study found.

Sex Chromosomes and Sex Determination

In humans and many other animals, specific chromosomes determine sex. But how did researchers discover these so-called sex chromosomes?

Sex Chromosomes Hold the Secret to Female Longevity

Now, scientists at UC San Francisco have zeroed in on a possible genetic mechanism for this highly durable phenomenon, that – while it does not preclude the influence of other biological, social and environmental factors – suggests an important role for the second X chromosome, which is present in female mammals. The X chromosome contains many genes related to the brain, and it is crucial for survival. Without at least one X, an animal cannot live. The Y chromosome, present only in males, contains very few genes other than those that create secondary sex characteristics, like male genitals and facial hair, and it is not necessary for survival.

Sex chromosomes responsible for much more than determining sex

Human sex chromosomes originated from a pair of autosomes, the ordinary or non-sex chromosomes that contain the majority of our genome and come in identical pairs. That ancestral pair of autosomes diverged to become two different chromosomes, X and Y. Even though X and Y have grown apart from each other and taken on unique functions—namely, determining sex and driving sex differences in males and females—they also retain shared functions inherited from their common ancestor.

Sex determination: The X, Y, Z’s of sex chromosomes

Lately it seems like my social media feed is filled to the brim with gender reveal parties where an expectant couple learns the sex of their baby. Party guests look on as the happy couple cuts into a cake or pops a balloon to reveal pink or blue confetti. Most of us were taught as early as grade school that there is a 50/50 chance that a human baby will be a male or female. Later in our education we learned that an X chromosome from mom and an X chromosome from dad makes a genetic female, while an X chromosome from mom and a Y chromosome from dad makes a genetic male.

The X and Y of sex differences

My interest in this topic has led me to study children who do not inherit the normal complement of sex chromosomes. These include girls with a single X chromosome (XO, Turner syndrome), girls with three X chromosomes (triple X or XXX syndrome), and boys with an extra X (XXY or Klinefelter’s syndrome), and boys with an extra Y (XYY syndrome).

What your science teacher told you about sex chromosomes is wrong

When I first got into this subject, I just assumed that X and Y were always known as the sex chromosomes — meaning that they were naturally and obviously the markers of sex. But as I got into the history, I realized that the X and Y chromosomes were known as anything but the sex chromosomes for the first 20 to 30 years after they were discovered.

When a Person Is Neither XX nor XY: A Q&A with Geneticist Eric Vilain

Eric Vilain discusses the biology and politics of mixed-sex individuals, arguing that terms such as "hermaphrodite" and "intersex" are vague and hurtful.

X and Y

As the noted scholars Salt N Pepa once said – “let’s talk about sex [chromosomes]”. Everybody’s got them – those of us born female have two X chromosomes, while males have one X and one Y chromosome. There’s also a minority of people who are born with different numbers and combinations of sex chromosomes, and who might consider themselves female, male or intersex, although we won’t go into more depth on that here (and, of course, your biological sex does not determine your gender identity – plenty of people who identify as men have XX and as women have XY and frankly that’s no-one’s business but theirs).

X Y Chromosomes

X and Y chromosomes determine not only the sex of an individual, but many broad characteristics as well. From grip-strength to aggression, there are myriad differences between men and women beyond simply their sexual organs. This is known as sexual dimorphism and is found in most species.

X&Y Chromosome Variations

Males usually have one X and one Y chromosome, and females usually have two X chromosomes. Occasionally, because of problems with the formation of a parent’s sperm or egg, a child can be born with extra or too few sex chromosomes.

Resources

Association for X and Y Chromosome Variations

AXYS, the Association for X and Y Chromosome Variations, is an advocacy, education and support organization for individuals with X and Y chromosome variations and their families. This includes those with Klinefelter syndrome (47,XXY), Trisomy X (47,XXX), 47,XYY, 48,XXYY, 48,XXXY and related genetic conditions.

The Focus Foundation

The Focus Foundation is dedicated to helping children and families affected by X & Y Variations, Dyslexia, and/or Developmental Dyspraxia. The Focus Foundation believes that through increased awareness, early identification and syndrome-specific treatment, children with these conditions can reach their full potential.