The formation of the vulva or penis starts occurring by the 6th week of pregnancy. Female and male fetuses look quite similar during the first-trimester ultrasound until about the 14th week of pregnancy.
There is a theory, called the Ramzi theory, that suggests that you can predict the sex of a fetus by as early as the 6th week of pregnancy by looking at the placement of the placenta on an ultrasound image. The theory says that it’s possible to tell the sex of a fetus by checking which side of the uterus the fetus is on. Nevertheless, there’s no scientific evidence to support this method.
You can also find out the sex of your baby by having noninvasive prenatal testing (NIPT), a blood test, which is usually done between 11 and 14 weeks of pregnancy.
Genetic testing methods such as amniocentesis or chorionic villus sampling (CVS) can also reveal the sex of your baby. Health care providers generally perform CVS between the 11th and 14th weeks of pregnancy and amniocentesis, between the 15th and 20th weeks. These tests are primarily done when the health care provider suspects fetal abnormalities, and the tests pose certain risks. Experts don’t recommend these tests only to determine the sex of the fetus.
You can find out if the fetus is male or female during an ultrasound done between the 18th and 22nd weeks of pregnancy. By the 18th week, your health care provider may be able to determine the sex of your baby if they are lying in a position that makes their genitals visible. If the health care provider can’t see the fetus’s genitals clearly, they may not be able to tell the sex for sure.
Here are the most popular methods for determining the baby’s sex in detail. We’ve outlined their accuracy in determining the sex of your baby.
The first-trimester screening is usually done between weeks 11 and 14.
There are two steps to this screening: a blood test and an ultrasound scan.
NIPT is a blood test that specifically checks for Down syndrome, trisomy 18, extra or missing copies of X/Y chromosomes, and other types of chromosomal abnormalities. This test can also detect fetal DNA present in your blood, which may help determine whether the fetus is female or male. You can discuss with your health care provider whether this blood test is appropriate for you or not.
An ultrasound is one of the early methods for predicting a fetus’s sex. Between the 18th and 22nd weeks of pregnancy, your health care provider may be able to determine the sex of the fetus during an ultrasound. They may examine the fetus’s genitals and look for different signs that will suggest if they are female or male.
As already stated, even during an ultrasound scan, the health care provider may not be able to find out the sex of the fetus. They may be lying in a position where their genitals are not visible. If this happens, you may need a repeat ultrasound scan. If you are having twins, determining the sex becomes even more of a challenge. Being able to accurately determine the sex of the fetuses depends on the ultrasound operator’s experience and if they’re using a high-resolution machine.
Ultrasound signs for determining the baby’s sex
There are some particular things that technicians and health care providers look for in ultrasound pictures to find out the sex of a fetus. These include:
Visualization of genitals — Before the resolution of ultrasound imaging was as high as it is today, health care providers tried to find a penis to determine if the fetus was male. If the health care provider didn’t find a penis on the ultrasound, then the fetus was assumed to be female. Nowadays, it is possible to see the vulva, clitoris, and labia in a female fetus and the scrotum, penis, and descended testicles in males. However, during the first-trimester ultrasound, the shape and size of the penis and clitoris are roughly the same. Health care providers use something called the sagittal sign and the direction of the genital tubercle to help determine the sex from the 11th week of pregnancy. The first-trimester ultrasound sex determination has a significant false-negative rate.
The hamburger sign (or 3-line sign) — Another sign on an ultrasound that indicates that your baby may be female is the hamburger sign (appearing as three lines). A female fetus’s genitals may look like a hamburger, with the clitoris situated between the two labia.
The turtle sign — The turtle sign on an ultrasound indicates that the fetus may be male. In the turtle sign, the tip of the penis appears to peek out from behind the testicles. This sign is difficult to see in some fetuses. Because of this, health care providers look for multiple signs in an ultrasound to determine the sex of a fetus.
An erect penis — Male fetuses can have erections even in the uterus. If your health care provider is looking at the ultrasound scan at just the right moment, they may notice a penis that is very clearly defined. This makes determining the sex of a fetus much easier.
Genetic testing methods such as amniocentesis or CVS can also be early prediction methods for determining the sex of the fetus. Health care providers generally perform these tests to determine if the fetus has a chromosomal abnormality or genetic disorder such as Down syndrome. They can obtain information about the fetus’s sex simultaneously. Experts don’t recommend genetic testing only to determine sex, as it has certain associated risks.
Amniocentesis is a type of genetic testing where the health care provider takes a small quantity of amniotic fluid from the uterus using a long, thin needle. Some of the fetus’s cells are present in the amniotic fluid, which can be used to determine the presence of any genetic disorders as well as the sex of your baby. Health care providers generally perform amniocentesis between the 15th and 20th weeks of pregnancy.
CVS is also a type of genetic testing used to determine the presence of any congenital defects such as Down syndrome as well as the sex of the fetus. During this procedure, your health care provider removes a sample from the chorionic villi, which is tissue present in the placenta that contains information about the fetus’s genes. Health care providers generally perform CVS between the 10th and 12th weeks of pregnancy.
Genetic testing methods may increase the risk of miscarriage, and they are generally reserved for pregnant people over the age of 35, couples who have a family history of genetic disorders, or to confirm a positive result from prenatal screening. Make sure to talk to your health care provider about whether these testing methods are appropriate for you.
There is no evidence to back up the Ramzi method, so it’s no better than a guess. Ramzi method claims to determine the sex of a fetus by as early as the 6th week of pregnancy. According to Ramzi theory, the placement of the placenta can determine the sex of the fetus. If the placenta is on the right side, then the fetus is male. If the placenta is on the left side, then the fetus is female. Once again, there is no evidence that this theory is accurate.
Ultrasounds can be quite accurate in predicting the sex of the fetus when done between the 18th and 22nd weeks of pregnancy. But mistakes still happen. For instance, if your BMI (body mass index) falls within the obese range, you’re carrying twins, or if the fetus is lying in a position that makes their genitals hard to see, it may be difficult to determine the sex with an ultrasound.
Genetic testing methods such as amniocentesis and CVS are extremely accurate in predicting the sex of a fetus. However, as already stated above, they may carry a risk of miscarriage, so they are not appropriate for everyone.
There is no evidence to back up the Ramzi theory of sex prediction. It’s just a guess.
It may be harder to find out the sex if you are having twins or more, as the fetuses may obscure each other and make it difficult to determine the sex of each.