Gender vs. Sex

Expecting parents often celebrate learning about the sex of their baby with a “gender reveal”—a party trend that’s evolved to include colored confetti canons and even custom cakes.

But are sex and gender the same thing?

Wherever you are in your SneakPeek® test journey—giddily checking the mail for your test kit or constantly refreshing your email for your results—you may have questions about the terms “sex” and “gender.” While both terms describe certain human characteristics, sex and gender are distinct labels that aren’t as straightforward as most people think. By shedding light on this topic, you can create a more inclusive and supportive environment for yourself, your baby, and those close to you.

Sex vs. Gender: Quick Definitions

The National Society of Genetic Counselors (NSGC) is an organization dedicated to increasing access to quality genetic counseling through education and advocacy. Since ideas of sex and gender are often tied to genetics, here’s how the NSGC defines these:¹

• Sex – “Sex is a concept used to describe people based on characteristics such as internal and external genitalia, chromosomes, and hormones.” Sex is typically assigned at birth by a medical professional based on some of these characteristics, though usually only genitalia.
• Gender – “Gender describes the self-understanding of being a man, woman, both, non-binary, different gender, or agender.” Essentially, gender is an identity every person develops in their own time as they grow into themselves.

Looking Beyond Definitions

Of course, definitions alone can’t fully encompass all the nuances of these two concepts. The NSGC also notes that:¹

• Sex does not determine gender. They are distinct concepts.
• Both sex and gender are dynamic, multi-dimensional, and non-binary—meaning they aren’t this or that, or either/or.

Beyond XX and XY

One of the ways medical professionals learn about a baby’s sex is by looking at their DNA—their sex chromosomes, to be exact.² But things aren’t always as simple as XX=female and XY=male.

While those are the most common pairings, many people have varying numbers and combinations of sex chromosomes. For instance:

• Trios like XXX, XXY, or XYY (known as trisomies)
• Monosomies, like X
• Tetrasomies and petrasomies, which feature four and five sex chromosomes, respectively

These variations are just some examples of how sex chromosomes don’t always conform to the typical XX or XY pattern and may not fit neatly into the binary categories of “male” or “female.” They represent merely one aspect of biological diversity and don’t automatically determine how a person is categorized.

That said, people with such variations may be categorized as intersex: a range of variations where an individual’s sex characteristics don’t fit typical definitions of “male” or “female.” Intersex people make up about 1.7% of the population—in the U.S. alone, that’s over 5.9 million people.³

Intersex traits can also be associated with variations beyond the sex chromosomes, including genetic, hormonal, or physical differences that influence sex characteristics. This further complicates the notion of clear-cut sex categories, challenging the binary approach to sex.

It’s important to note that sex chromosome variations and intersex traits don’t point to something “wrong” with a person. They’re simply another way the human body demonstrates diversity.

How Sex Characteristics Develop

Chromosomes aren’t the only factors that influence sex. Babies develop many sex characteristics during gestation (and throughout childhood and adolescent development) that play a role.⁴

Where Does Gender Come In?

The season doesn’t always dictate the weather. The amount of sleep you get doesn’t always reflect your restfulness in the morning. Similarly, sex assigned at birth doesn’t necessarily indicate a person’s gender.

For example, though someone may have male sex characteristics (XY sex chromosomes, testes, penis, etc.) and be assigned male at birth, they may not identify as a boy. The same goes for people assigned female at birth.

Although a majority of people identify their gender with their sex assigned at birth (known as cisgender), these two concepts are not always aligned. Many people are transgender, agender, non-binary, or other labels.

Almost 1% of U.S. adults are transgender, and another 1.7% choose not to identify with man, woman, or transgender, using other gender-nonconforming labels—or no label at all.⁵ And this community is only growing: According to Pew Research Center, about 5% of young adults under 30 are gender diverse.⁶

Why Sex and Gender Education Matters

Using the terms “sex” and “gender” with an understanding of their true meanings creates a more inclusive environment that embraces differences and supports all people, including your children and loved ones. Not to mention, it’s more scientifically accurate.

Here are some other helpful sex- and gender-inclusive terms to know:

1. Sex assigned at birth – This identifies someone as assigned female at birth (AFAB) or assigned male at birth (AMAB), rather than simply “female” or “male.” Using this terminology helps reinforce the nuances of sex assigned at birth.
2. Gender identity – How someone understands their gender internally.
3. Gender expression – How someone presents their gender externally, through clothing, makeup, hairstyle, and more.

In the case that your child or other loved one finds themselves exploring their gender, this self-education matters: Studies show that supportive parents are one of the most important factors in a child’s well-being and academic success.⁷

How to Interpret Your SneakPeek Test Results

During pregnancy, little pieces of fetal DNA are released from the placenta and into your bloodstream. The SneakPeek® Early Gender Test looks for Y chromosome DNA in your blood to help you learn about your baby’s sex. The presence of Y chromosomes in your blood suggests “male,” while their absence suggests “female.”

This is how the test can predict your baby’s sex chromosomes at just 6 weeks into pregnancy with more than 99% accuracy.⁸

But remember: Sex chromosomes are merely one factor that influences a baby’s sex, and it doesn’t determine their gender. It’s just a single facet of the one-of-a-kind bundle of joy you’re bringing into the world.