When can you find out the gender of your baby? The short answer: an at-home blood test can give a fairly reliable read from about 7 weeks, NIPT from about 10 weeks, and the mid-pregnancy anatomy scan, at 18 to 22 weeks, is when most people find out. Tests before 7 weeks, and anything using urine, are unreliable.
Strictly, these tests detect your baby's sex: whether Y-chromosome DNA is present, or what the genitals look like on a scan. Most people search for "gender", so we use both words here. Here's what each option involves, when it becomes possible, and how much to trust it.
Key takeaways
- A large review of fetal-sex blood tests found them unreliable before 7 weeks (they missed about 1 in 4 boys) and about 95% sensitive from 7 to 20 weeks (Devaney et al., JAMA 2011).
- The same review found urine-based gender tests unreliable at any stage.
- NIPT, the screening blood test your provider may offer for chromosomal conditions, can report sex chromosomes from about 10 weeks (ACOG).
- Most people find out at the anatomy scan between 18 and 22 weeks; on the NHS this is the 20-week scan, where you may be asked if you'd like to know.
- Folklore methods such as the Chinese gender calendar perform at about chance level.
When Can You Find Out Your Baby's Gender, Week by Week?
You can find out your baby's gender from about 7 weeks with an early blood test, from about 10 weeks with NIPT, and at 18 to 22 weeks on an anatomy ultrasound. The invasive tests, CVS and amniocentesis, also show sex chromosomes but are only offered for medical reasons.
| Week of pregnancy | Option | How it works | How much to trust it |
|---|---|---|---|
| Any time | Folklore (Chinese calendar, old wives' tales) | Dates, cravings, symptoms | About chance level |
| Before 7 weeks | At-home gender blood test | Looks for Y-chromosome DNA in your blood | Unreliable: misses many boys |
| 7–10 weeks onward | At-home gender blood test | Same, now with more fetal DNA in your blood | About 95% sensitive in research |
| About 10 weeks onward | NIPT (ordered by your provider) | Screens fetal DNA for chromosomal conditions; sex chromosomes can be reported | High, but still a screening test |
| 10–13 weeks | CVS | Samples placental tissue | Diagnostic; offered only for medical reasons |
| 12–14 weeks | Early ultrasound "nub" guess | Angle of the genital tubercle | A guess, often wrong at this stage |
| 15–20 weeks | Amniocentesis | Samples amniotic fluid | Diagnostic; offered only for medical reasons |
| 18–22 weeks | Anatomy scan | Sonographer looks at the genitals | Usually clear, depends on baby's position |
How Early Can a Gender Blood Test Tell You?
A gender blood test can tell you with reasonable reliability from about 7 weeks of pregnancy, not earlier. These tests look for fragments of Y-chromosome DNA from the placenta in your bloodstream: if they find it, the result is "boy"; if they don't, it's "girl".
That last step is why timing matters so much. In early pregnancy there is very little fetal DNA in your blood, so a boy can be missed and reported as a girl. In the JAMA meta-analysis of 57 studies, blood tests done before 7 weeks detected only 74.5% of boys. That rose to 94.8% at 7–12 weeks and 99% after 20 weeks. The same review judged urine tests unreliable.
At-home kits (you prick your finger and post a sample to a lab) are built on this method. If you use one:
- Count weeks from the first day of your last period, and wait until the kit's minimum week, preferably 8 or later.
- Treat a "girl" result as less certain than a "boy" result, since a missed Y signal reads as female.
- A male partner, older son or anyone male handling the sample can contaminate it and produce a false "boy".
- Confirm with your anatomy scan before buying anything you can't return.
These kits aren't part of your medical care, so mention the result to your midwife or doctor rather than relying on it for anything important.
When Does NIPT Show the Baby's Sex?
NIPT can show your baby's sex chromosomes from about 10 weeks, as part of a screening test for conditions such as Down syndrome. It analyzes cell-free DNA from the placenta in your blood, as described in Mayo Clinic's overview of noninvasive prenatal testing.
The sex result is a by-product, not the main purpose. Your provider will usually ask whether you want it included in your report. ACOG's guidance on prenatal genetic screening stresses that NIPT estimates risk rather than diagnosing, so any unexpected result is followed up with diagnostic testing or ultrasound.
Coverage varies. In the US, insurance coverage of NIPT depends on your plan and your risk profile, so check with your provider if the cost matters.
When Does the Anatomy Ultrasound Show Baby's Sex?
Most parents find out at the anatomy scan between 18 and 22 weeks, when the sonographer can usually see the external genitals clearly. The scan's real job is checking your baby's organs and growth; seeing the sex is a bonus.
In the UK this is the NHS 20-week screening scan, usually done between 18 and 21 weeks, and the NHS notes you may be asked whether you'd like to know the sex. Policies vary between hospitals, so ask ahead if it matters to you.
How clearly the genitals show depends on your baby's position, the amount of fluid, and where the umbilical cord happens to be. If the sonographer can't get a clear view, it doesn't mean anything is wrong. It usually just means another look at a later appointment.
Some providers will offer a guess at 12 to 14 weeks based on the angle of the genital tubercle (the "nub"). This is much less reliable than the anatomy scan, so don't paint the nursery on it.
How Accurate Are the Different Methods?
Lab tests on fetal DNA or placental tissue are the most accurate, a clear anatomy scan is close behind, and folklore is no better than a coin flip. Here is how they compare once each method's timing is right:
| Method | Accuracy in practice | Main way it goes wrong |
|---|---|---|
| CVS or amniocentesis | Diagnostic | Rarely wrong; not offered just to learn sex |
| NIPT | High | Low fetal DNA, a vanished twin, or rare chromosomal differences |
| At-home blood test, 7+ weeks | About 95% sensitive in research | Testing too early, or sample contamination |
| Anatomy scan, 18–22 weeks | Usually clear | Baby's position or a poor view |
| Nub ultrasound, 12–14 weeks | Often wrong | Too early to see clearly |
| Folklore | About 50% | It isn't measuring anything |
If you want an answer you can plan around, use a lab-based test at the right week or wait for the anatomy scan.
What About the Chinese Gender Calendar and Other Folklore?
Folklore methods like the Chinese gender calendar are fun to try, but they predict sex at about chance level. A 2010 study in Paediatric and Perinatal Epidemiology tested the chart against 2.8 million Swedish births and found it no better than a coin flip.
If you'd like a lighthearted guess while you wait, try the Chinese gender calendar or the baby gender predictor, which runs three traditional methods side by side. The calendar page explains how the Chinese chart works, and our guides on old wives' tales about baby gender and whether morning sickness predicts gender explain where these ideas come from.
Frequently Asked Questions
What is the earliest you can find out the gender of your baby?
About 7 weeks, with an at-home gender blood test. Before 7 weeks these tests miss many boys, so wait if you can. NIPT from your provider can report sex from about 10 weeks.
Can you find out the gender at 8 weeks?
Yes, an at-home blood test at 8 weeks is in the window where research found about 95% sensitivity for detecting boys. A "girl" result is slightly less certain than a "boy" result, so confirm it at your anatomy scan.
Can you find out the gender at 12 weeks?
Usually yes, if you've had NIPT or an early blood test by then. A 12-week ultrasound can only offer a "nub" guess, which is far less reliable than the 18–22 week scan.
Is the 20-week scan accurate for gender?
It is usually accurate when the sonographer gets a clear view. If your baby is curled up or the angle is poor, they may say they can't tell, and you can ask for another look later.
Are urine gender tests accurate?
No. The JAMA review of fetal-sex testing found urine-based tests unreliable, so a urine "gender predictor" kit is no more trustworthy than folklore.
Why did my ultrasound technician say they weren't sure?
Usually because of your baby's position, the scan angle, or the amount of fluid that day. It doesn't mean anything is wrong.
The Bottom Line
You can find out the gender of your baby from about 7 weeks with an at-home blood test, from about 10 weeks with NIPT, or at the 18–22 week anatomy scan, which is when most people learn it. Earlier tests and urine tests aren't reliable, and folklore is a fun guess rather than an answer. If you want to know where you are in the timeline right now, the due date calculator shows your current week, and your midwife or doctor can tell you which tests are offered where you live.