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Are you having a boy or a girl? What test can help? Sneak peek?

Ultimate Guide for Finding Out The Sex Of Your Baby

Are you one of those mommies/daddies to-be that has NO patience finding out whether you’re having a boy or a girl? After all, waiting until the 20-week anatomy scan is waaaay too long? Right?… Right?

Great, glad it’s not just me!

It’s safe to say that I’m definitely more of a “finding-out-sooner-rather-than-later” person.


First Things First: Sex vs. Gender

At the risk of sounding insanely pretentious, this is a tiny bit of a pet peeve of mine. Does it really matter whether you say “sex” or “gender” when talking about being a boy or girl? Not really.

Buuttttt (ahh you knew this was coming)….

The boy and girl parts of your future baby are called its “sex”. “Sex” and “gender” are often used interchangeably, but in science, it’s referred to as “sex” when talking about biological characteristics. Generally, you’ll see two X chromosomes in girls, and one X chromosome and one Y chromosome in boys.

“Gender” is not a biological term. It refers to the socially constructed characteristics of women and men. Sure, in the vast majority of cases sex and gender are basically the same. But sometimes, it is not.

“Sex” is basically your biology, while “gender” can be different between people or societies, and it is more fluid.

But let’s move on. I promise you I won’t get mad if you still refer to it as gender. I’ve even heard my doctor mention it interchangeably!


Is it a Boy or a Girl?

Now that we’ve settled that debate. I’ve been told that there are many women out there who don’t want to find out what they’re having. There’s even a name for it: “Team Green“.

In fact, in the US, 42% of fathers and mothers prefer to find out the sex only after birth. In Western Europe, the percentage of parents not wanting to find out is a little bit lower, at 31%.

Well. I think it’s safe to say that even though there are geographical differences, the vast majority of couples still want to find out if they’re having a boy or a girl.

And we’re definitely one of those couples who not just wanted to find out, but also wanted to find out as soon as possible!

Call me weird, but I’m not a big fan of surprises.

While it doesn’t matter to us what we’re having, knowing about it does matter.

After all, “overpreparation” is my middle name.

  • Do I have to read up on the benefits vs dangers of circumcision?
  • Do I have to start painting the nursery pink or blue?

 So, how can you find out the sex of your baby, and more importantly: how early?!


Can a Urine Test Detect The Baby’s Sex?

Maybe you’ve seen those gender prediction tests kits that supposedly “predict” whether you’re having a boy or girl?

Let me be frank. Please, please, just skip them, it’s a total waste of money.

Let me quote from the actual product description (as of October 2018): “This product is not for people who are looking for a 100% accurate result.” They then go on and say “There [sic] not a single gender test on this earth that is perfect” … “Even DNA tests have a risk of the result not being 100% accurate.”

Wow, now that’s a false equivalency if I ever saw one! A more honest statement would’ve been “this totally not-random-at-all 50% accurate test may suck, but so does that >99% accurate DNA test!”

The final nail in the coffin is that 46% of people give it a 1-star review.


That is pretty damn close to 50%, wouldn’t you say?

Since having a boy or girl is basically a flip of the coin, any random test will always be right… about 50% of the time.


Use ultrasound to determine sex?

When Can An Ultrasound Tell You The Baby’s Sex?

Usually, a second-trimester ultrasound is needed to find out the sex of the baby.

There ARE actually certain signs a sonographer can look for to determine whether the genitalia will develop in boy parts or girl parts early in the first trimester. But I’ve never heard of an ultrasound tech actually doing this in the real world, not for a routine ultrasound anyway.

Let’s just say it: if you’re basing your intel on an ultrasound it’s probably not a great idea to schedule that gender-reveal party in the first trimester! (Yes, I called it a gender-reveal party, I have to admit, sex-reveal party sounds very weird ;))

Even well into the second trimester, the accuracy is dependent on the skills of the sonographer and whether the baby wants to cooperate. But generally speaking, if the sonographer feels comfortable enough to tell you if you’re having a boy or a girl, they’re right between 95-100% of the time.


The Holy Grail? “Non-Invasive Prenatal Testing”

Eff screwing around with random urine tests or waiting for the 20-week scan! The most reliable way of finding out what you’re having is through a simple blood DNA test.

Did you know that a pregnant woman’s blood contains DNA particles of her baby? That’s right! The further along you are, the more cute baby-DNA there’s floatin’ around in mom’s blood!

This method is called cell-free DNA (cfDNA) testing, or non-invasive prenatal screening (NIPS/NIPT). It’s a pretty new technology that is used to screen the baby for certain chromosomal abnormalities, such as Down syndrome. In the United States (this is not available in all countries!) you can also check a box that allows you to find out (with >99% certainty) the sex of your baby.

These tests go by many different names such as Harmony, MaterniT, Panorama, Claritest, and QNatal.

The only caveat is that there has to be enough fetal DNA circulating in your blood for the test to be accurate, which is why most doctors don’t offer the test before the 10th week of pregnancy.

I’ll write more about NIPT screening in a future blog post, it’s a really cool technique that deserves its own (looong) post.

But if you’ve decided against NIPT screening (no insurance coverage, too expensive, moral grounds, or feel that it’s unnecessary), there’s yet another way of finding out what you’re having, very early on.


Enter The “Sneak Peek” DNA Test

Remember I said how NIPT looks for fetal DNA circulating in the mom’s blood? Well, so does the “gender” Sneak Peek test.

This simple blood test’s only goal is to find out –with very high accuracy– the sex of your baby. It works the exact same way as the NIPT test: by looking for fetal DNA in your blood. Instead of looking for all kinds of chromosomal abnormalities which make the NIPT very expensive, the Sneak Peek test simply checks for the presence of a Y-chromosome.

If your baby is a boy, a Y-chromosome will be present in your blood. If it’s a girl, no Y-chromosome will be found.

You can even do the test at home, all you need is a drop of blood from your fingertip. You send it back to the lab, and a week later you have the result.

What’s not to like? It’s 99% accurate, it’s inexpensive, and you get to do it all from the comfort of your home.

I can already hear you saying: “But what about all the 1-star reviews on Amazon! Isn’t this just another scam?”

Well… There’s a couple of things to keep in mind:

  • The Sneak Peek test won’t be accurate before 9 weeks of pregnancy
  • The Sneak Peek test won’t be accurate if you have twins or triplets
  • The Sneak Peek test won’t be accurate if the sample is contaminated (e.g. with your partners’ DNA)
  • And, of course, it won’t tell you anything about chromosomal abnormalities. For that, you’d need to get an actual NIPT.

So yes, it’s very accurate as long as you keep those caveats in mind.

Instead of a sneak peek test, I got an actual NIPT test done (the Claritest) at 11 weeks of pregnancy, so I don’t have any personal experience with this product. But I can say that the science behind it is sound.

If you can’t wait to find out the sex of your baby, this is by far the cheapest, easiest and most reliable method of doing so. And no, I’m not getting paid by Sneak Peek to say so (but Sneak Peek management, if you’re reading this, feel free to send a check my way!), I just like the science and simplicity behind it.


Oh. And in case you were wondering… we are expecting a little girl! 😀


  • Kelley

    October 8, 2018 at 2:54 pm

    Congratulations!!! And thank you for continuing to share your research and your journey. Your blog has helped us become confident enough to choose a clinic and book our own treatment. We are headed to Gennet for our first try at IVF this month. Congratulations again!!!

    • Mrs Frugalcrib

      October 8, 2018 at 4:19 pm

      Ahh thank you so much Kelley 🙂 Good luck next month! It’s a scary, yet exciting, thing to go abroad for IVF. I hope you’ll keep us posted on how things are going. Wishing you all the best!


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