9 Scientific & Semi-Scientific Ways To Predict Baby Gender

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“Am I Having A Boy Or A Girl?”

The day you find out about your pregnancy, you may keep thinking of ways to determine the gender of the baby. With various old wives’ tales and scientific ways to predict baby gender, many expectant parents would want to try these methods to find out if they are going to welcome a little prince or princess. However, you must note that these tests may not be authentic and medically reliable. Also, if you plan to go for scientific methods, you must know if finding out a baby’s gender is legal in your country. Browse through this post to discover some scientific, not-so-scientific, and fun ways to detect the gender of your unborn baby.

Scientific Ways To Predict The Sex Of A Baby

These are the standard medical ways to determine the sex of your unborn baby. However, they can be considered only if sex determination is legal in your country.

1. Ultrasound scan

Ultrasound scan is the most common method used by doctors. Ultrasounds are high-frequency sound waves that produce images of the fetus.

The procedure is usually performed to look at the development of the fetus, where the waves are sent over the stomach through the uterus. The waves then create a picture of the unborn baby, which can be viewed on a monitor. The doctor will be able to know if it is a boy or girl based on the position of the fetus by recognizing the genitals if the scan is done after 18 weeks when the reproductive organs start to appear (1). However, the doctor will not tell you about the sex of your baby, if prenatal sex determination tests are illegal in your country.

2. Amniocentesis and chorionic villus sampling (CVS)

These two tests are performed if your baby is at risk of having genetic or chromosomal abnormalities. As it can detect fetal chromosomes, it can also identify the sex of the baby.

Amniocentesis involves inserting a thin needle into the uterus through your abdomen to withdraw a small sample of fluid and analyze chromosomes. It is performed after the 15th week of pregnancy. CVS involves the extraction of a small tissue sample from the placenta, which can contain the genetic information of your baby. This is usually performed in the 11th week of pregnancy (2).

3. Cell-free DNA test

This test uses blood samples to detect the sex of the fetus.

The procedure uses small strands of DNA found in the bloodstream of the mother, and the test screens for the presence of male chromosome Y. If they detect the Y chromosome, there is a high chance of having a boy, and if not, it will be a girl. They are performed after 10 weeks of pregnancy and beyond. The accuracy rate is 95% to 99% (3).

Semi-Scientific Ways To Predict The Baby’s Sex

Some methods rely partly on tests and science but may not always be accurate.

4. Ramzi theory abdominal ultrasound

Developed by Dr. Saam Ramzi Ismail, it is also referred to as the Ramzi sex determination method or Ramzi’s method.

The method uses placental location as a marker for detecting the sex of the fetus. The placental side is known through the ultrasound scan, done at six to fourteen weeks into pregnancy (4). If the placenta is towards the right side, it is said to be a boy, and if it is to the left, it might be a girl.

5. The skull gender test theory

This theory is based on observing the skull shape of your baby to determine its sex. An ultrasound picture would help the doctor guess the cranial differences.

In general, male skulls are believed to be larger and robust than female skulls (5).

6. The Nub theory

This checks for the “the angle of the dangle” or the nub. It can be determined in the 12th-week ultrasound picture.

In the first trimester, the fetus will have a genital tubercle, otherwise known as the nub, which develops later into a penis or clitoris. You are likely to carry a boy if the nub points towards the baby’s head. And it might be a girl if the nub remains flat or points down (6).

Fun Ways To Predict Sex Of A Baby

Next, we list some off-the-wall sex prediction tests that have no basis in facts. They are random methods based on people’s beliefs and misconceptions and have no scientific backing whatsoever.

7. Chinese gender prediction chart

The Ancient Chinese gender chart uses the mother’s age at the time of conception and the month of conception to predict the baby’s sex based on the Chinese lunar calendar. According to this chart, you may conceive a girl if both your date of birth and conception month are either odd or even. The chart says you’ll have a boy if one date is even and the other odd (7). Want to give it a try? Use our Chinese gender predictor chart.

8. Wedding ring test

This is one of the oldest and most popular sex prediction tests done using the wedding ring and a string. It can be tried at any time, and most people prefer to play during baby shower parties. However, there is no scientific evidence to support this method.

You have to tie the wedding ring to a thread or a piece of hair and hold the swinging ring over the belly when lying down. If the ring moves back and forth, like a pendulum movement, it is said to be a boy. If the ring moves in a circular motion, it’s said to be a girl (8).

9. The baking soda gender test theory

This is another unscientific gender test theory and an easy DIY experiment based on old wives’ tales.

Mix a cup of clear urine with a couple of tea spoons of baking soda. It is said to be a boy if the mixture bubbles up or fizzes and a girl if it stays calm with no reaction. Truth is, baking soda’s reaction with hCG is believed to create bubbles like the ones you find after opening a soda pop.

While some of the gender prediction methods could be fun and quite an indulgence, you cannot rely on them for accuracy.

Frequently Asked Questions

1. What’s the difference between a girl bump and a boy bump?

It is believed that prominent bellies indicate a boy since boys weigh more at birth than girls. There is also a theory that weight spread around the hips might indicate a girl. In contrast, excess weight in the front may indicate a male. However, none of these claims are proven and might not be accurate.

2. What are the chances my baby will be a boy?

The man’s chromosome at the time of conception determines the biological gender of a baby. The male contributes an X or a Y chromosome during conception. Based on the chromosome the male’s sperm contributes, there is a 50-50 chance of the baby being a boy or a girl.

It is an exciting and emotional feeling when you know the sex of the fetus. Relying on scientific gender predictions rather than the other techniques may be more accurate and thus give you a head start to make preparations accordingly for your baby boy or girl. However, before proceeding, do check your country’s guidelines for sex determination since certain countries such as India consider it illegal. If it is legal, go ahead and celebrate your baby’s arrival with a grand gender reveal party if you wish to.

Disclaimer: Sex prediction methods are only for fun and do not replace medical examinations. MomJunction believes in gender equality. We do not support or encourage sex determination nor entertain any queries on finding the sex of the baby.


MomJunction's articles are written after analyzing the research works of expert authors and institutions. Our references consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
1. Prenatal Ultrasound; UC San Diego Health
2. Celine Lewis et al.; Non-invasive prenatal diagnosis for fetal sex determination: benefits and disadvantages from the service users’ perspective; Eur J Hum Genet. (2012)
3. Stephanie A. Devaney et al.; Noninvasive Fetal Sex Determination Using Cell-Free Fetal DNA; JAMA (2015)
4. Michael McFadzen et al.; Maternal Intuition of Fetal Gender; J Patient Cent Res Rev. (2017)
5. K. Ramakrishnan et al.; Sex determination in forensic odontology: A review; J Pharm Bioallied Sci. (2015)
6. Patricia Santiago-Munoz; Boy or girl? The difficulties of early gender prediction; The University of Texas Southwestern Medical Center (2016)
7. Villamor E et al.; Accuracy of the Chinese lunar calendar method to predict a baby’s sex: a population-based study; Paediatric and Perinatal Epidemiology. (2010)
8. Wedding Ring Test – Pregnancy Gender Predictor; USC Digital Folklore Archives (2013)
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Rebecca Malachi

Rebecca is a pregnancy writer and editor with a passion for delivering research-based and engaging content in areas of fertility, pregnancy, birth, and post-pregnancy. She did her graduation in Biotechnology and Genetics from Loyola Academy, Osmania University and obtained a certification in ‘Nutrition and Lifestyle in Pregnancy’ from Ludwig Maximilian University of Munich (LMU). She has been into health and... more

Dr. Anita Gondy

Dr. Anita Gondy is an Ob/Gyn at The Ob-Gyn Center in Las Vegas. In practice since 1998, Dr. Gondy began her medical training at Rangaraya Medical College in Kakinada, India and completed studies at the University of Nevada School of Medicine, where she also did an obstetrics and gynecology residency. She is also a Fellow member of The American College... more