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Which chromosome does a male XX pass along?
Are there any exceptions to XX chromosomes?
What are sex chromosomes?
Learn about the X and Y chromosomes that determine biological sex in humans and other mammals. Find out how sex-linked traits, sex-chromosome disorders, and differences of sex development affect individuals.
- Autosomes
Autosome, any of the numbered or nonsex chromosomes of an...
- Klinefelter Syndrome
Although about 40 percent of men affected by Klinefelter...
- Autosomes
- Overview
- What are sex chromosomes for?
- What’s the difference between primary and secondary sex determination?
- What is a difference in sexual development (DSD)?
- Other frequently asked questions
- The bottom line
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A chromosome is a DNA molecule that contains genetic material. Sex chromosomes are chromosomes that affect your sexual anatomy and reproductive development.
Most of us were raised with the idea that there are two sexes: male and female. We’re usually told that people with XY chromosomes are male and people with XX chromosomes are female.
It’s a lot more complicated than that.
Typically, there are 46 chromosomes in each human cell. This usually includes a pair of sex chromosomes and 22 pairs of autosomes. Autosomes are all chromosomes that are not sex chromosomes.
Many people are born with variations in sex chromosomes, also called X and Y variations or sex chromosome aneuploidy (SCA).
People with an SCA may have one X chromosome, XXY chromosomes, XXX chromosomes, and so on.
Sex chromosomes typically determine the development of your reproductive organs and your secondary sex characteristics.
For example, your sex chromosomes may determine:
•the hormones your body produces
•whether you have ovaries or testes
•the development of breast tissue
Having certain sex chromosomes may also make you more susceptible to specific health conditions. For example, hemophilia A and B are sex-linked conditions more likely to appear in people with XY chromosomes.
Primary sex determination depends on chromosomes. Secondary sex determination depends mostly on hormones.
Primary sex characteristics include the gonads, which are the glands that produce reproductive hormones in the body.
Secondary sex characteristics are determined by the hormones the gonads secrete. These characteristics include your body’s phenotype (how it looks) outside of the reproductive system.
Examples of secondary sex characteristics include:
•enlarged breasts
•wider hips
Many people have a difference in sexual development (DSD), which is also called intersex. “DSD” is a term that describes chromosomes, sex characteristics, and anatomy that can’t be defined as exclusively male or female.
As many as 1 in 100 people are born with a DSD.
Not everyone with a DSD has variations in sex chromosomes. Some people with DSDs may have XX or XY chromosomes. But they might also have X and Y variations or SCA.
Variations in sex chromosomes can include:
•45,X (Turner syndrome)
•47,XXY (Klinefelter syndrome)
How many sexes are there?
If you look this up, you’ll undoubtedly find a variety of opinions on the matter. Some say there are only two sexes, while others say there are an infinite number of sexes. It depends on your definition of sex: What makes a specific phenotype a “sex”? How do you determine the difference between a sex category and a sex variation? It’s hard to say. Many biologists assert that sex is a spectrum and not a binary, meaning there are many variations in sex and not simply two exclusive categories. Gender and sex are different things — but gender is also not a binary.
How many people are born intersex?
As many as 1 in 100 people are born with a difference in sex development (DSD), which is another term for intersex. According to the Intersex Society of North America, about 1 in 1,500 to 1 in 2,000 people are determined intersex at birth. However, some intersex people only find out about their DSD later on in life, like at puberty or as an adult. It’s even possible to have intersex traits and never know. This number depends on how you define “intersex.” Many people have variations in sex differences that are not apparent to others. As such, some clinicians might not consider them intersex.
What are karyotypes?
Your karyotype is your complete set of chromosomes. A karyotype is used to visualize the appearance of your chromosomes, including the size, number, and shape of the chromosomes.
Sex chromosomes determine the development of your gonads. But sex chromosomes are a lot more complex than most people think.
While we’re typically taught that there are only two sex chromosome types — XX and XY — the truth is there are more variations than that.
Learn about sex chromosomes, which affect your sexual anatomy and reproductive development. Find out the differences between primary and secondary sex determination, intersex, and variations in sex chromosomes.
- Sian Ferguson
In the XY sex-determination system, the female-provided ovum contributes an X chromosome and the male-provided sperm contributes either an X chromosome or a Y chromosome, resulting in female (XX) or male (XY) offspring, respectively.
Learn how sex chromosomes (X and Y) determine biological sex and affect gene inheritance patterns in humans and other organisms. Explore examples of X-linked genes, disorders, and how they differ from autosomal genes.
- In the second paragraph of the section titled "Sex Chromosomes in Humans", do Chromosomally female (...Hi Tanya, my understanding is that XX individuals with an SRY translocation (who develop as male-bodied) may need hormone supplementation at pubert...
- "SRY is found on the Y chromosome and encodes a protein that *turns on other genes* required for mal...I'm not an expert on this, but my understanding is that SRY† is (usually) sufficient for embryonic testis formation and that the hormonal effects o...
- What is Gene-linkage? How is it different from the Sex-Linkage?Sex linkage referes to a gene being linked to (or "on") a sex chromosome. Gene linkage refers to two genes that are on the same chromosome, and are...
- It says in the 2nd paragraph of 'sex chromosomes in humans' that the X chromosome has 800-900 protei...Any time you have dominant and recessive alleles of a gene it is only the dominant allele that gets expressed. There doesn't have to be a second al...
- If the father is colorblind, but the mother is not, then their children can't be colorblind. The mal...Yes, that is correct.
- How does the XY chromosomes relate the the blood type of the offspringBlood type is not a sex-linked trait. Its an autosomal trait determined by gene I located on chromosome 9. The gene I has 3 allelic forms, Ia, Ib a...
- I hope someone will answer this question: what happens if the father has the disease, how will it af...well, depends on if disease is dominant or recesive and what the mother has
- What is hemizygous?Hemizygous is a term used to describe an individual who has only one member of a chromosome pair or chromosome segment rather than the usual two.
May 15, 2022 · The nuclei of human cells contain 22 autosomes and 2 sex chromosomes. In females, the sex chromosomes are the 2 X chromosomes. Males have one X chromosome and one Y chromosome. The presence of the Y chromosome is decisive for unleashing the developmental program that leads to a baby boy.
Sex chromosomes (also referred to as allosomes, heterotypical chromosome, gonosomes, heterochromosomes, or idiochromosomes) are chromosomes that carry the genes that determine the sex of an individual. The human sex chromosomes are a typical pair of mammal allosomes.
Sex is determined by specific chromosomes in humans and many other animal species. The XX-XY system is one of the most common, where maleness is determined by sperm cells with the Y chromosome and femaleness by eggs with two X chromosomes. Learn how researchers discovered these so-called sex chromosomes and how they work in different systems.
