Nub Theory Gender Prediction - Does It Work?

Nub Theory

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When you learn that you are pregnant, you usually wonder whether the baby will be a boy or a girl. If you already have a daughter, you may want your next baby to be a son or vice versa. If you plan to have more than two kids, you may have your personal preferences. Waiting for weeks together to know the gender seems long. Gender predicting tools were born to address this inquisitiveness in soon-to-be parents. There are various methods of predicting a baby’s gender. Here we talk about the nub theory of gender prediction, and whether it works.

However, you need to realize that ultrasound scans are the best way to predict your baby’s gender.

Understanding The Nub Theory Of Gender Prediction:

Usually, you will have to wait till about 20 weeks of your pregnancy to identify the sex of your baby with an ultrasound. However, there is a theory now that claims it can determine the gender of the baby as early as 12 weeks. Popularly known as the Nub Theory, more and more desperate parents to be who are too inclined on knowing the sex of their baby are banking on this theory.

The Nub Theory uses the ultrasound images from between 11 and 12 weeks of gestation. The theory studies the genital area of the baby as visible in the ultrasound to predict the sex. Typically, babies of both genders at this age have similar genital area. At this age, both boys and girls have a genital tubercle or nub (something akin to the penis), which either becomes a penis (in males) or clitoris (in females). It is looking at this nub’s position that doctors and sonographers can predict the gender of a fetus [1].

[ Read: Is Ultrasound Safe During Pregnancy ]

What Is A Nub?

As mentioned earlier, both boy and girl fetuses have a genital tubercle in the initial stages of development. This genital tubercle is called a nub. At about nine weeks of gestation, the nub in the boy and the girl looks almost identical, but with a minor difference. Because the genitals look so similar, and more so because the nub gives an appearance of a small penis, an ultrasound scan will not be able to determine if you are carrying a boy or a girl.

But wait, doctors can analyze the angle of the nub to determine the gender [2]. That is what the Nub Theory is all about.

Nub Theory states that the angle of the nub or the angle of the dangle can predict the gender. Strangely, this theory has a high degree of accuracy. As per the theory, a boy’s nub dangles at a 30-degree angle or more when the fetus is lying prone on its back, whereas a girl’s nub is more or less parallel to lower part of the spine.

How Does The Nub Theory Work?

To determine the sex of your baby as early as 12 weeks using the Nub Theory, you will need your ultrasound images. The nub angle is visible in the side profile image of the baby. You will have to compare the angle of the nub in relation to the baby’s lower spine.

The side view of the baby in an ultrasound image is known as the sagittal plane. Hence, the angle of the nub is referred to as the sagittal sign. This is how you can determine if you are carrying a boy or a girl using the sagittal sign:

1. Mark The Baseline:

Take the sagittal image of your ultrasound scan and determine the baby’s base spine. Draw a baseline through the lumbosacral skin surface. The lumbosacral is the lowest part of your baby’s back, just above the tailbone. This baseline becomes the reference point for your Nub Theory.

2. Draw The Nub Line:

The next thing you will need to do is identify the nub. Ultrasound images are not always very clear, and you may have to spend some time locating the nub. You may want to view several ultrasound images from the same week of your pregnancy to ensure you are identifying the nub correctly. Once you do so, draw a line across the nub.

[ Read: Scientific Methods Of Gender Prediction During Pregnancy ]

3. Determine The Angle Of The Nub:

Now, you have two lines on your ultrasound image – the baseline and the nub line. You have to determine the angle between the two lines. If the angle is more than 30 degrees, you can predict your baby will be a boy. On the other hand, if the angle is less than 10 degrees or the nub line is parallel to the baseline, it will be a girl. On the other hand, if the angle is between 10 and 30 degrees, the result is inconclusive. Should this happen, you may want to repeat the scan in a couple of days.

The Perfect Nub Shot

Determining the gender of your baby using the Nub Theory depends, to a large extent, on the picture of the ultrasound. This means the nub shot has to be perfect for you to determine the result. So, if you want to use an ultrasound image for Nub Theory, here are a few things to keep in mind.

1. Schedule The Scan At 12 Weeks Of Pregnancy Or Later:

The accuracy of the Nub Theory is best after 12 weeks of gestation. Many believe the theory is most accurate during the 13th week. This is based on the gestational age of your baby by baby’s CRL (crown-rump length).

If you are a plump mom-to-be, waiting another week is a good idea. Since there is more abdominal tissue if you are plump, it may obscure the image of the baby.

2. Get A Profile View Of The Baby With A Straight Spine:

When you are getting your ultrasound, ask the sonographer to capture the sagittal plane view of your baby. Also, insist on having a picture where the baby’s spine is relatively straight. Just being able to see the nub is not sufficient. You also have to be able to determine the angle of the dangle relative to the spine. Remember, the sagittal view is the only nub shot that will help you.

[ Read: 12th Week Pregnancy ]

3. Drink Lots Of Water In The Week Before The Ultrasound:

The more amniotic fluid you have, the clearer will be your ultrasound image. Hence, you should consume ample water a week or two before you are due for an ultrasound. This can help increase the volume of the fluid in your womb.

4. Make Your Baby A Little Active:

To capture the baby right, you may want your baby to be a little active during the ultrasound. This will ensure that your baby moves a little, and the sonographer can capture the right nub shot. Have a glass of orange juice or apple juice about 30 minutes before the scan. Anecdotal evidence claims this can make babies more active in-utero.

How Do Gender Experts Predict Gender Using Nub Theory?

Gender experts can predict the sex of your baby using the Nub Theory. These experts depend on the visibility of the genital tubercle. This visibility can be affected by the position of your baby and whether he is active or snoozing. The amount of amniotic fluid, the thickness of the abdominal wall, and the scan quality can also be determinants in predicting the gender of your baby using the Nub Theory.

The following are the important criteria that gender experts use when predicting the sex of a baby using the Nub Theory:

  • Visibility
  • The nub’s angle in relation to the baby’s spine
  • The shadows on and around the nub captured in the scan
  • The length and shape of the baby as per the gestational age

Before the 10th week of pregnancy, the genital tubercle appears similar in boy and girl fetuses. At 11 weeks, visibility becomes clearer, and it may be possible to predict the gender of your baby at this stage but in perfect conditions. The accuracy of Nub Theory is the highest in the 12th week of gestation and beyond.

[ Read: Ring On A String Gender Prediction ]

Accuracy Of The Nub Theory

You may be skeptical, but Nub Theory is a scientific theory used for gender determination. Unlike the old wives tales, this theory doesn’t consider illogical explanations to find out the sex of your baby. However, the accuracy of the theory depends on the timing your ultrasound.

1. 11th Week:

Though the sex organs of your baby start developing internally by about nine weeks, they are not externally visible even by the 11th week. Most of the times, the nub’s angle in the 11th-week scan is inconclusive (between 10 and 30 degrees). Even if the nub’s angle is visible, it may change over the next few weeks. The accuracy of the Nub Theory is debatable at this stage.

2. 12th Week:

This is the time when the baby’s external genitals start showing clear signs of gender inclination. At this stage, only about 7% of the nubs are inclusive. The accuracy of the theory at this juncture stands at 98%.

3. 13th week:

There is a miniscule chance of getting the theory wrong at this stage of pregnancy. Prediction accuracy of Nub Theory stands at almost 100% by the 13th week of gestation. So if you use the theory correctly, you should be able to predict the sex of your baby quite accurately.

[ Read: Symptoms Of Baby Girl During Pregnancy ]

Nub Theory: Importance Of Gender Prediction:

Gender determination in pregnancy may seem superfluous to many of us. You may feel that it only feeds the curiosity of the expectant parents and encourages selective family planning. On the contrary, gender determination becomes crucial medically in certain cases when the parents stand a chance to pass sex-linked diseases to their babies. Many sex-linked disorders affect just male offspring. Hence, determining the sex of the baby early in the pregnancy can allow parents to opt for genetic counseling and be emotionally and mentally prepared before the birth of their child.

If the Nub Theory identifies the baby as a girl child, it becomes easier for the parents. They do not feel the need to perform any other invasive or non-invasive tests to find the chromosomal abnormality. On the other hand, if the Nub Theory predicts a boy, further tests can help evaluate the fetal viability and other health concerns related to the unborn baby.

Gender Prediction During Pregnancy:

In most cases, the talk about your baby’s gender is usually harmless and often associated with fun. Yes, there are many myths around it, but in most cases, expectant parents are aware that none of the unscientific ways to predict the baby’s gender is anything to go by. However, you need to be wary of gender if:

  • The gender determination process is contradictory to the medical advice of your OB/GYN.
  • Somebody gives you something to ingest that is not approved or recommended by your doctor.
  • If the process stresses you out. Stress may pass on to your baby and interfere with his growth and development.

Other Ways To Predict The Gender Of Your Baby:

There are some scientific ways to predict the gender of your baby. Ultrasound, amniocentesis, chorionic villi sampling (CVS), and noninvasive prenatal testing (NIPT) are the scientific ways which give more or less accurate results.

[ Read: Chorionic Villus Sampling During Pregnancy ]

1. Non-Invasive Prenatal Testing (NIPT):

NIPT is a blood test to determine the gender of your baby and for the presence of certain chromosomal conditions. Usually, you can have this test as early as nine weeks of your pregnancy, and it is the test of choice for high-risk pregnancies.

2. Amniocentesis:

Amniocentesis is a procedure that involves inserting a needle into your womb to extract a little bit of the amniotic fluid and analyzing it in the laboratory. This test allows doctors to find out whether the baby has any genetic disorder. It also can determine the sex of the baby. Usually, your doctor will perform this test by 15 weeks of gestation.

3. Chorionic Villi Sampling:

As the name suggests, Chorionic Villi Sampling involves taking a sample of the chorionic villi from the placenta by the 10th week of pregnancy. This too is the test of choice for high-risk pregnancies, but can predict the gender of the baby.

4. Ultrasound:

Your OB/GYN will perform an ultrasound when a blood test confirms your pregnancy. This is to ensure your baby is growing healthily. It allows the doctor to catch any abnormality or defect in the growth early. The test also can predict the sex of your baby, but regulations mandate that the doctor should perform this non-invasive test just for medical reasons.

Fetal ultrasound is a good way to predict the gender of your baby, but this is done only in the second trimester. Expect the ultrasound between the 18th and the 22nd week of your pregnancy. During this time, the baby’s genitals are fully formed, and the doctor will be able to identify the gender of the baby. But, the question is – can you wait that long?

You should also remember that chorionic villi sampling and amniocentesis can result in miscarriage. Hence, you should take the decision to have either test only if your doctor recommends it, and not because you want to know the gender of your little one.

[ Read: Chinese Gender Prediction ]

Common Pregnancy Myths Related To A Baby’s Gender:

Pregnancy myths (or the old wives tales about pregnancy-related concerns) vary from region to region and generation to generation. Nevertheless, here are some common pregnancy myths associated with determining the gender of your baby. You may already know a few of these myths. In fact, your mother-in-law or other elderly female members of your family may have already told you about these myths during your pregnancy.

Myth 1: The Shape Of Your Belly Determines The Sex Of Your Baby:

There is a popular belief that women carrying low tend to have boys while those with a high belly end up with girls!

Myth 2: Fetal Heart Rate Can Indicate Your Baby’s Gender:

Slow fetal heart rate (lower than 140 bpm) means a boy, and a higher rate indicates you are going to have a baby girl.

Myth 3: The Shape And Fullness Of Your Face Determine The Gender Of Your Baby:

Weight gain is common during pregnancy, and most women dread it. But the same weight often becomes a sex predictor. If your face has a rounder and rosier appearance, don’t be surprised if people tell you that you will have a boy.

You should take these pregnancy myths with a pinch of salt. They can be entertaining while you are pregnant and give you a few laughs. But don’t base the sex of your baby on these myths.

[ Read: Widely Believed Pregnancy Myths ]

Nub Theory has been studied scientifically, and a few research papers have been published related to this theory. The accuracy of Nub Theory is near-perfect when used at the correct time with clear scan images.

As a parent, you shouldn’t worry about the sex of your baby. If you want to decorate the nursery or buy baby stuff, opt for gender-neutral designs and colors. Ultimately, having a healthy baby is more important than wondering about your little one’s gender.
Do you prefer to know your baby’s gender before-hand or would want it to be a surprise. Let us know by commenting below.

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