When it comes to your baby’s sex, can you always trust your ultrasound scan results? The answer is simple: no. That’s true, experienced sonographers’ projections for girls and boys aren’t always accurate.
Learn more about gender ultrasound accuracy and how physicians decide whether you’re expecting a boy or a girl.
How Accurate Are Pregnancy Gender Scans?
Ultrasound scans are one of the most common methods used to determine a baby’s gender during pregnancy.
In most cases, gender scans are highly accurate when performed by experienced sonographers using modern ultrasound equipment.
Typical accuracy rates:
14–16 weeks: around 90–95% accuracy
16–20 weeks: around 95–99% accuracy
After 20 weeks: accuracy is usually above 99% if the baby’s position allows clear visibility
Accuracy improves as the pregnancy progresses because the baby’s genital anatomy becomes easier to see during the scan.
However, ultrasound interpretation still depends on image clarity and fetal position, which means mistakes can occasionally occur.
Why Can an Ultrasound Get the Baby’s Gender Wrong?
Although gender scan errors are rare, there are several reasons why an ultrasound might incorrectly identify a baby’s sex.
1. Baby Position During the Scan
The most common reason for incorrect gender prediction is the baby’s position.
If the baby’s legs are crossed or the genital area is hidden, the sonographer may not get a clear view.
When this happens, the scan may either:
- produce an incorrect prediction
- or the sonographer may be unable to confirm the gender at all.
2. The Scan Is Performed Too Early
Early pregnancy scans can sometimes lead to incorrect gender predictions.
Before 14–15 weeks, male and female genitalia can appear very similar on ultrasound images. This makes early gender determination less reliable.
This is why most clinics recommend gender scans from 16 weeks onward for better accuracy.
3. Umbilical Cord Confusion
Sometimes the umbilical cord can be mistaken for male genitalia, particularly if it is positioned between the baby’s legs.
This may cause the ultrasound to incorrectly suggest the baby is a boy.
4. Image Quality and Maternal Factors
Ultrasound image clarity can be affected by several factors, including:
- fetal movement
- maternal body tissue
- placenta position
- ultrasound machine quality
If the image is not clear, it may increase the chance of incorrect interpretation.
Can an Ultrasound Be Wrong About Gender at 32 Weeks?
It is very unlikely for an ultrasound to be wrong about gender at 32 weeks, but it is still technically possible.
By this stage of pregnancy:
- the baby’s anatomy is fully developed
- the genital area is easier to identify
- the accuracy rate is typically above 99%.
However, unusual fetal positioning or limited visibility may occasionally make gender identification difficult.
Can the 20-Week Anomaly Scan Be Wrong About Gender?
The 20-week anomaly scan is one of the most reliable times to determine a baby’s gender.
At this stage:
- genital anatomy is clearly developed
- ultrasound imaging is usually very detailed
- sonographers have a better chance of getting a clear view.
While mistakes are rare, they can still happen if:
- the baby moves during the scan
- the genital area is partially hidden
the image quality is poor.
Ultrasound Says Girl — Could It Actually Be a Boy?
Yes, although it is uncommon.
In some cases, parents are told they are expecting a girl but later discover they are having a boy.
This can happen if:
- the penis is hidden between the baby’s legs
- the baby’s position blocks the view
- the umbilical cord is mistaken for genital anatomy.
These situations are rare, but they explain why ultrasound gender predictions are not considered 100% guaranteed.
What Are the Chances of Having a Boy When the Ultrasound Says Girl?
If an ultrasound predicts a girl, the chances of the baby actually being a boy are very small.
Most studies suggest ultrasound gender predictions are correct in more than 95% of cases.
The likelihood of an incorrect result is higher when:
the scan is performed early in pregnancy
visibility is limited
the baby’s position obstructs the view.
Ultrasound vs Blood Tests for Baby Gender
Some parents choose to confirm their baby’s gender using different medical tests.
Here is how ultrasound compares with other gender detection methods.
NIPT (Non-Invasive Prenatal Testing) analyses fetal DNA in the mother’s blood and can determine gender earlier than ultrasound.
However, ultrasound scans remain popular because they allow parents to see their baby and check development at the same time.
When Should You Trust a Gender Scan Result?
A gender scan is most reliable when:
- the pregnancy is 16 weeks or later
- the baby’s genital area is clearly visible
- the scan is performed by an experienced sonographer
- high-quality ultrasound equipment is used.
If the sonographer has a clear view, gender predictions are usually extremely accurate.
What Should You Do If You Think the Scan Is Wrong?
If you believe your ultrasound result may be incorrect, you have several options.
You can:
schedule a repeat gender scan later in pregnancy
request confirmation during your 20-week anomaly scan
consider a NIPT blood test for earlier confirmation.
Many parents choose a second scan simply for reassurance.
FAQ: Pregnancy Gender Scans
1. Can an anomaly scan be wrong about gender?
Yes, but it is rare. The 20-week anomaly scan usually provides a very clear view of the baby’s anatomy, making gender identification highly accurate.
2. Can ultrasound be wrong about gender at 32 weeks?
It is extremely uncommon but still possible if the baby’s position blocks the genital area or the ultrasound image is unclear.
3. Ultrasound says girl — could it be a boy?
Yes, although the chances are small. Sometimes the baby’s position hides male anatomy, leading to a mistaken prediction.
4. When is the best time to find out baby gender?
The most reliable time to determine gender with ultrasound is between 16 and 22 weeks of pregnancy.
5. Are private gender scans accurate?
Private gender scans performed by experienced sonographers using modern ultrasound equipment are typically 95–99% accurate.
Conclusion
Ultrasound gender scans are generally very accurate, especially after 16–20 weeks of pregnancy. However, no scan is completely foolproof. Factors such as baby position, early scans, and image quality can occasionally lead to incorrect predictions.
If you want greater certainty, you can confirm the results with a later ultrasound scan or a prenatal blood test.
For most parents, though, gender scans provide an exciting and reliable way to learn more about their baby during pregnancy.
