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  2. Pregnancy health
  3. Prenatal testing

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Boy or Girl? Early Signs of Your Baby’s Sex

We’ve all heard about which boy or girl early signs can help pregnant women predict their baby’s sex. But do you actually know how sex is determined, and which of these signs are true or false? Read this article to learn more about your baby’s sex.

Why to know the sex before giving birth?

When you find out that you’re pregnant, the number one thing you wish for is to have a healthy baby. But the baby’s sex can also be on your mind from the moment you get a positive pregnancy test! In the end, families are happy to welcome their healthy new addition regardless of sex.

You might have been thinking about unisex baby names, and discovering your baby’s sex could make you want a different name. Or hey, those names could also make amazing names for twins if you get a surprise! 

When do babies develop their sex?

The process through which gender is determined is called human sexual differentiation. You won’t find out about your baby’s gender until your pregnancy is a few months along, but it has already been set in stone from the moment of conception.

The baby’s genes determine sex. All eggs contain an X chromosome, while sperm can have an X or a Y chromosome. If the egg is fertilized by a sperm cell carrying an X chromosome, the resulting XX embryo will be a girl. On the contrary, if the sperm cell has a Y chromosome, the embryo will have male XY chromosomes.

At first, all embryos look the same regardless of sex. In fact, if it wasn’t for the effects of testosterone, all babies would develop female traits. Until week 7 of your pregnancy, your baby will have a structure called a “genital ridge”. Then, over the next 5 weeks, your baby starts producing hormones that stimulate the development of its sexual organs.

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All the sexual organs come from the genital ridge. The ovaries and labia are equivalent to the testicles it means they are formed from the same cells, just like the clitoris and the penis. So once those hormones kick in, the genital ridge begins differentiating into these structures.

In boys, the genital ridge starts to lengthen into a penis by week 9. Tiny buds will form the prostate around week 10, and the urinary system is formed by week 14. Testicles descend into the scrotum around week 26, and the penis keeps growing during the third trimester.

In girls, ovaries develop between weeks 11 and 12, and they fill up with 7 million of primitive eggs. These eggs will reduce in quantity up until birth, and your baby girl will be born with approximately 2 million eggs in her ovaries. Two structures called the paramesonephric ducts fuse to form the uterus and vagina during the third month of pregnancy. The vagina will open up around week 22.

5 signs that you’re having a girl

There are plenty of popular beliefs and myths that claim to predict early boy or girl signs. And while it’s tempting to think that you can absolutely determine your baby’s gender through physical symptoms, medical research has debunked many of these myths. Here is the truth about 5 supposed pregnancy signs for a girl:

Carrying the baby high

One of the most common myths surrounding baby gender says that having a higher bump means you’re having a girl. However, this has been shown to be a myth.

The biggest factors that determine the way your bump looks are your physical condition, the amount of pregnancies you’ve had, your abdominal muscles physical shape, and your total weight gain during pregnancy.

Being stressed out before conception

Another popular belief is that your stress levels before you get pregnant can play a role in determining your baby’s gender. And surprisingly, scientific studies have found a correlation between these two facts.

A study revealed that women with higher cortisol levels - the stress hormone -were more likely to have a girl. However, the reason for this hasn’t been discovered yet.

Mood swings

Some people think that the estrogen that baby girls produce can affect the mother’s humour, causing mood swings. However, scientific studies have found that this isn’t true.

All pregnant women can suffer from mood swings due to their own hormones fluctuating during gestation. But these mood changes aren’t related to your baby’s gender!

Having more morning sickness

Another popular belief states that since girls produce more hormones, their mothers will suffer from a more severe case of morning sickness. But science and experience have both shown that morning sickness can vary from women to women. The same women can even experience different levels of morning sickness during different pregnancies.

One study, published in the medical journal The Lancet, did find a small correlation between severe morning sickness and the probability of having a girl. However, their evidence wasn’t conclusive, so this myth remains… well, a myth.

Having acne or dull skin

Have you ever heard the saying that a baby girl steals her mother’s beauty? Some people believe that if you’re having a girl, you’ll develop oily or dull skin, and lots of acne. But this is just another false belief. Pregnancy hormone can be unpredictable, and they’ll affect each woman’s skin and hair differently.

5 signs that you’re having a boy

Craving salty foods

Research has shown that anywhere between 50% to 90% of all pregnant women experience food cravings at some point during their pregnancy. And a popular belief states that women carrying girls will crave more sweets. They also think that if you’re having a boy, you’ll crave mostly savory and salty foods.

The truth is that a woman’s cravings are more likely to be related to their nutritional requirements than to the gender of their baby. So this one isn’t really a pregnancy symptom for a boy.

Lower fetal heart rate

Another baby sex myth claims that if your baby’s heart rate is around 140 beats per minute, it’s a boy. A faster heartbeat would mean that you’re carrying a girl. But scientific studies have shown that there isn’t a significant difference between the heartbeats of female and male fetuses. In fact, male fetuses tend to have a slightly faster heartbeat, but it’s only by about 3 beats per minute.

Carrying low

Just like carrying high is supposed to mean that you’re having a baby, it’s widely believed that a lower bump means your baby is a boy. But there’s no evidence to back up this theory. As we stated above, the shape of your bump is determined by other factors. 

Healthier hair and skin

This is the opposite of the myth that having a girl will “take away your beauty”. A lot of people believe that if you’re carrying a boy, your skin will look healthier and you’ll have thick, lustrous hair.

But in reality, these changes depend solely on pregnancy hormones. Some women can develop skin pigmentation or acne, while others will have thicker hair and a “pregnancy glow”.

No mood swings

Does anyone really believe that having a boy means that pregnant women will avoid mood swings? Unfortunately, it’s not true! You’re just as likely to experience mood swings whether you’re having a boy or a girl. They’re a very common occurrence for many pregnant women.

Medical tests to learn your baby's gender

All in all, it’s no wonder that many people believe in these myths. After all, they always have a 50% chance of being right. But how can you determine your baby’s gender without any doubts?

These are some of the tests that your doctor can use to determine your baby’s gender:

Blood tests

Special blood tests can determine your baby’s gender. These tests are usually only carried out on women over the age of 35, or those with an increased risk of chromosomal disorders.


This test is also carried out mostly on high-risk pregnancies. Using a sample of amniotic fluid, it can detect genetic abnormalities and your baby’s gender.

Chorionic villus sampling (CVS)

This test uses a sample of placenta to diagnose Down syndrome or another chromosomal abnormality. It can also determine the baby’s gender as early as week 10 of pregnancy.


This is the most common way to determine your baby’s gender. And it’s what most women carrying low-risk pregnancies will experience. An ultrasound technician could see your baby’s gender as early as 15-16 weeks, but most women will find out during their second trimester ultrasound.

Final note

It’s normal to want to know your baby’s sex, but having a healthy mom and a healthy baby are always more important. Maintain a healthy nutrition during pregnancy, keep an eye out for the fluids you consume during pregnancy, keep your water intake high, stay active, and pretty soon you’ll find out whether you’re pregnant with a boy or a girl!


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