How to conceive a boy or a girl: Can you choose the sex of your baby?

In this article, we’ll explore the medical methods that allow you to choose your baby’s sex, alongside the many DIY approaches that don’t hold up to science. We’ll also delve into myths that persist about gender selection, and touch on the ethical and societal considerations that come into play.

Can I choose the sex of my baby?

The short answer: Yes, but only with medical intervention through preimplantation genetic diagnosis (PGD), which is done after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) [1]. And even then, this intervention is only permitted for medical reasons, not for the purpose of choosing your baby’s sex. 

Over the years, plenty of DIY or “natural” methods have gained popularity. These include timing intercourse with ovulation (like the Shettles and Whelan methods described below), dietary tweaks, supplements, and even commercial kits. While some families swear by them, none are scientifically proven to guarantee results.

Before diving into the different approaches — both medical and unproven — here are some broader considerations to keep in mind.

Sex at birth versus gender identity

When we talk about choosing sex, we’re referring to biological sex as determined by chromosomes — male (XY) or female (XX). However, sex is not the same as gender identity, which is how a person experiences and identifies themself later in life. Even if sex is selected before birth, it does not determine how that child will feel, express themselves, or identify in the future [2, 3]. 

Ethical questions

Sex selection raises complicated ethical questions, especially when it comes to gender biases. For this reason, many experts believe medical techniques like PGD should be reserved for preventing serious genetic disease, not for choosing the sex of your baby [4]. On a personal level, it’s worth reflecting on why one might prefer a boy or a girl, and whether that preference is tied to cultural expectations or assumptions about gender roles. 

Methods for choosing the sex of your child

There’s a lot of unreliable information out there. Here, we unpack the scientific (and not so scientific) methodology to help you better understand your reproductive journey. 

Timed intercourse based on ovulation: fertile days for a boy or a girl 

One of the most popular theories for swaying your baby’s sex is timed intercourse — planning when to have sex in relation to ovulation. The idea is that X- and Y-bearing sperm behave differently and may respond to changing conditions in a woman’s body across her cycle. By syncing sex with these fertile days, these theories claim you can tilt the odds toward conceiving a boy or a girl. The two best-known approaches are the Shettles and Whelan methods.

How it works: According to the Shettles Method, sperm carrying a Y chromosome (for a boy) are thought to swim faster but die off sooner, while sperm carrying an X chromosome (for a girl) move more slowly but survive longer in the female reproductive tract [5]. 

The Whelan Method suggests that a woman’s body creates different biochemical environments throughout the cycle. These shifts, depending on how many days remain before ovulation, may make conditions more favorable to one type of sperm over the other [6].

Shettles Method

• To conceive a boy: Have sex as close to ovulation as possible, so that the fastest sperm will reach the egg first. 
• To conceive a girl: Have sex 2–3 days before ovulation, and abstain from sex right before ovulation to increase the chances that an X-bearing sperm (the ones that have survived longer after ejaculation) fertilizes the egg. 

Shettles also suggests certain sex positions and even female douching techniques as part of the method. Note: Douching can actually be harmful for your vagina, so we don’t recommend it!

Whelan Method:

• To conceive a boy, couples should have intercourse 4–6 days before ovulation.
• To conceive a girl, couples should have intercourse closer to ovulation day (2–3 days).

Reliability: Scientific research does not support timed intercourse methods as a reliable way to choose your baby’s sex. A study from 1995 found no reliable link between intercourse timing and a baby’s sex [7].

Considerations: Following these methods and restricting sex to certain days may actually reduce your overall chances of conceiving, since sperm survival decreases during the time it would be ‘waiting’ to reach the egg. Ultimately, while the Shettles and Whelan methods are popular at-home approaches, they should be understood as unproven and should not replace focusing on overall fertility health and well-being.

At-home kits 

Commercial products claim to sway the odds of conceiving a boy or girl by altering your body’s pH levels.

How they work: These kits operate on the idea that changing vaginal pH can influence whether Y- or X-chromosome sperm are more likely to succeed (i.e. fertilize the egg). They often include pH test strips, dietary supplements, and guidance on timing intercourse, drawing on principles from timing-based methods like Shettles.

Reliability & considerations: These at-home kits aren’t backed by solid scientific proof. Timing intercourse has been disproven as a method for sex selection, and the evidence around pH levels for this purpose is very limited [8]. Given the lack of scientific evidence, at-home kits should be approached with caution (and at Natural Cycles, we do not endorse them). It’s important to speak with your doctor or a fertility specialist before trying any at-home sex selection methods (and the same goes for trying new supplements). Any method that is not prescribed by your doctor and involves putting things in your vagina can lead to problems like infections or irritations. 

Medical methods: preimplantation genetic diagnosis and sperm sorting

Preimplantation genetic diagnosis (PGD)

This is a medical procedure used during in vitro fertilization (IVF) or Intracytoplasmic Sperm Injection (ICSI) allows parents to select an embryo of a certain sex [9].

How it works: IVF/ICSI is a process where eggs are collected from the ovaries and fertilized with sperm in a lab to create embryos. These embryos can then be tested for their sex chromosomes, and parents may choose which embryo to transfer into the uterus. It’s important to note that not all IVF cycles will result in embryos of both sexes, so some parents will not have the option to choose sex through PGD.

Reliability & considerations: This method (PGD) is nearly 100% accurate, but it’s invasive, expensive, and usually offered for medical reasons (such as preventing sex-linked genetic conditions) rather than personal preference [10]. Regulations also vary widely: in countries like the UK, Canada, and much of Europe, non-medical sex selection is prohibited, while in others, including the U.S. and Mexico, it’s permitted [11, 14].

Sperm sorting

This is a laboratory method that separates sperm by sex prior to fertility treatments [12].

How it works: A machine separates the sperm by sex and uses the desired-sex sample for intrauterine insemination (IUI) or IVF/ICSI.

Reliability & considerations: Studies have shown that sperm sorting can shift the odds, but there are no guarantees. However, this method is far less reliable (when compared to PGD) and largely unavailable — once offered in the U.S., it was discontinued in 2012 and is currently only accessible in a few countries [12, 13,]. 

Debunking myths: fact versus fiction

When it comes to baby-making advice, myths are everywhere — and they can be entertaining, even charming at times. But misinformation around conception and women’s health isn’t harmless. It can add confusion, create pressure, and make people second-guess their own bodies. That’s why it’s worth separating fact from fiction when it comes to choosing a baby’s sex.

Below, we break down the most common claims you’ve probably heard. Spoiler alert: most of these tricks won’t change your odds.

1. Sex positions can determine a baby’s sex
   There is no conclusive evidence that sexual position has any effect on whether you conceive a boy or a girl [15].
   
   
2. Diet can sway the odds
   Some research suggests that a mother’s diet before conception may slightly influence which embryos are more likely to survive and implant. For example, higher energy intake and regular breakfast cereal consumption were linked with a greater chance of having a boy [16, 17]. However, these effects are small, not deterministic, and remain debated.
   
   
3. Genetics may influence sex
   Some research suggests that fathers who carry a particular gene variant tend to have more daughters. The gene influences the probability of having sons versus daughters, but it does not determine the sex of any particular child [18].
   
   
4. Having an orgasm can play a role
   While popularized by the Shettles Method, there is no proof that a woman’s orgasm during intercourse has an effect on the baby’s sex.

General tips to help conceive 

While there is no proven way to guarantee your baby’s sex (outside of medical intervention), supporting your overall fertility gives you the best chance of conceiving in general. 

Maintain a healthy diet and lifestyle: Balanced nutrition, moderate exercise, and limiting alcohol or smoking are great ways to support reproductive health for both partners [19].

Track your cycles carefully to identify fertile days: Knowing when you ovulate helps you time intercourse for conception (though not for sex selection). Ovulation can be tracked in a variety of ways, including by measuring your basal body temperature through Natural Cycles (more on that below). 

Seek preconception counseling: Preconception counseling looks at your overall health before you try to conceive. It helps identify any risks or health issues and supports you in creating the healthiest foundation possible for pregnancy [20]. 

Reduce stress: Stress can disrupt your menstrual cycle, so stress-management techniques like mindfulness, yoga, or counseling may help [21].

How do I know when I’ve ovulated?

Popular sex-selection methods hinge on timing intercourse around ovulation. While science doesn’t support these methods, knowing when you ovulate is still one of the most powerful tools for improving your chances of conception.

What is ovulation?

A key event in the menstrual cycle, ovulation is when an egg is released from the ovary and travels to the fallopian tubes, where it can be fertilized by sperm.

The most fertile window is the few days leading up to ovulation and the day it occurs — especially the two days before, when the chances of conception are at their peak. Timing sex around this window is key for conception, as the egg only survives for about 12–24 hours [22, 23].

When does ovulation happen?

Ovulation happens in the middle of your cycle. This means that for a 28-day cycle — the ‘textbook’ cycle length — ovulation occurs on day 14.

However, research (including our own study) shows there’s far more variation in cycle length beyond the 28-day cycle with ovulation on day 14. On average, cycles run closer to 29 days, with ovulation still tending to happen around the middle. However, the exact timing shifts and is highly individual. Tracking your cycle is far more accurate than relying on the old “day 14” rule of thumb.

Ways to track ovulation

There are a few different ways you can get to know your body better, find your fertile window, and predict and confirm ovulation. These include:

Measuring basal body temperature (BBT): Your resting body temperature rises slightly after ovulation. By taking your temperature each morning, you can detect patterns over time.

Cervical mucus monitoring: Around ovulation, cervical mucus becomes transparent and is similar to the consistency of an egg white — it’s a sign that your body is fertile. While keeping track of discharge can be a helpful tool to learn more about your fertility, it can be tricky to interpret, and it isn’t always a reliable fertility indicator [24].

At-home ovulation tests: These at-home urine tests detect the surge of luteinizing hormone (LH) that triggers ovulation. Ovulation tests can be a handy tool to predict ovulation, but they cannot guarantee that it will happen.

Switch to Natural Cycles: The first FDA-cleared birth control app, Natural Cycles can also be used to plan pregnancy. The app’s algorithm uses biometric data, such as temperature data to predict and confirm ovulation. Natural Cycles can be used with ovulation tests to help narrow down the fertile window, but this tool decreases the labor of other methods like manual charting or daily monitoring of cervical mucus.

Get pregnant faster with Natural Cycles

Thanks for reading all about sex selection and whether or not it’s possible to conceive a boy or a girl. This is a controversial and sometimes emotive issue, but with so much stigma and taboo around women’s health, it’s one that’s important to address!

If you’re on your journey to starting a family, keep in mind that tuning into your fertility with Natural Cycles can help you navigate the conception journey — and empower you to learn more about your body along the way. Natural Cycles supports your fertility goals by measuring body temperature, tracking ovulation, and highlighting your fertile days. Studies show couples using Natural Cycles to plan pregnancy conceive in three cycles on average [25]. Wherever you are in your journey — preventing pregnancy, trying to conceive, or navigating postpartum — find out how Natural Cycles can work for you.