Gender selection: how to conceive a boy or a girl

Everything you need to now about conceiving a boy or a girl...

a woman finds out if she conceived a boy or a girl
(Image credit: Getty Images)

If you're thinking about expanding your family, you might be thinking about gender selection - trying to conceive a boy or a girl.

Gender selection uses sperm selection methods and in vitro fertilisation techniques (IVF) to implant an embryo of either sex into a woman's womb. Gender selection using medical techniques are controversial and illegal in many parts of the world, including the UK. However, it is legal in some states of the USA. Aside from medical intervention, there are a lot of theories and Old Wives Tales about gender selection during conception. Natural methods some couples use include altering the timing and frequency of sex in the fertile window, to dietary changes. However, these are not guaranteed and the evidence behind the techniques is limited and varied.

If you're certain you want to dictate the gender of your baby, the only way to guarantee this is expensive, medical IVF techniques. These can be complex and controversial.  To find out about the medical evidence behind the varied techniques behind gender selection, we talked to Dr Gareth Nye, who is an expert in maternal and fetal health at the University of Chester. We also spoke to microbiologist Kathryn Taylor, author of the Babydust Method: A Guide to Conceiving A Boy Or A Girl (Amazon |£12) for her view on gender selection.

"Gender selection is most common for second time mums, especially those trying to conceive a girl. Women are the ones in control of their cycle so lead the process." - Kathryn Taylor, microbiologist and pioneer of  the natural Babydust method for gender selection at conception.

How does gender selection work?

Gender selection is deliberately trying to conceive a boy or a girl using in vitro fertilisation (IVF) methods and sometimes "sperm sorting". IVF involves the woman taking drugs to stimulate her ovaries to release several eggs, which a doctor then retrieves.

Your partner will also need to provide a sperm sample. Women without partners or same-sex female couples can use sperm donors.

The sperm and the egg are joined together in a laboratory and left for a few days to develop in laboratory conditions. Then the tiny, early embryos are examined to determine whether they will grow into female or male babies using preimplantation genetic diagnosis (PGD). This process was originally developed to allow scientists to analyse the embryos for any genetic abnormalities, especially conditions that only affect males or females.

Once the embryos are determined to be of the desired gender, they are implanted back into the woman.

How is a baby's gender decided?

Your baby's sex is determined by chromosomes. Chromosomes contain the basic DNA "instructions" to make a human. Half of your chromosomes come from your mother and half come from your father.

The sperm contains either X chromosomes (female) or Y chromosomes (male). The egg only contains X chromosomes. When they meet, the XY mix will produce a male and XX will produce a female.

Dr Gareth Nye explains: "The sex of your baby is determined in the most basic way at the moment when the sperm meets the egg. The baby then undergoes sexual differentiation during the pregnancy."

Gender selection for avoiding genetic illnesses

Sperm sorting methods; separating sperm into male sperm and female sperm used to be used for gender selection. This was sometimes done when a family had genetic illnesses that only ran in female or male lines. This method was previously unregulated in the UK but is now banned.

Dr Nye told us "There are good reasons for wanting to decide the sex of a baby when considering gender-specific diseases. However, technology is getting closer to removing these diseases, without the need for sperm sorting."

In vitro fertilisation of several embryos is the most successful method. The embryos are then tested for chromosomal abnormalities and the DNA is sequenced to determine whether they are male or female.

How much does gender selection cost?

Costings in the USA vary but the cost of one attempt to conceive a boy or a girl using IVF can range from $2000 USD to around $8000 USD.

However, many couples have to undergo several "rounds" of IVF treatment before an embryo successfully develops into a baby. There are also lab and testing fees and the costs of the drugs. Some couples say they have spent up to $100k to get the girl or boy they dreamed of.

Some couples who cannot afford medical gender selection or live in countries where it is banned, choose natural methods. These include faith in Old Wives Tales or trying to time conception according to various theories, as detailed below.

All medical methods for gender selection are illegal in the UK.

Sperm sorting (separating male and female sperm) was unregulated in the UK until 2003 and therefore legal.

"Sperm sorting" methods rely on determining the chromosomes in sperm before joining them with the egg. This method used to be unregulated in the UK but was banned by the government in 2003 after the Human Fertilisation and Embryology Authority (HFEA) recommended proper regulation.

"We are not persuaded that the likely benefits of permitting sex selection for social reasons are strong enough to outweigh the possible harm that might be done" - Suzi Leather, chair of the HFEA

Couples who cannot travel to seek medical methods of gender selection may try natural methods for gender selection.

What are the risks of gender selection?

Gender selection using medical methods is not without risks:

  • IVF is invasive and expensive and many couples find it tests their relationship
  • Risks to the woman involve bleeding and infection within the womb
  • Studies show there is a small risk of damage to a woman's organs from the egg retrieval process
  • Screening for the baby's gender is not 100% accurate (although it's very close!)
  • Screening for a baby's chromosomal abnormalities is also not 100% accurate

Some parents may find that they spend a huge amount of money on gender selection and still do not conceive, as these practices are not guaranteed. They may also find that there has been a mistake in the process and they, therefore, give birth to a baby of the opposite gender they desired.

IVF methods can take a toll on a couple's relationship and the treatments for the woman include the use of hormones - which, studies show, can affect mood. However, it's unclear whether it's the treatment itself, or the stress of the IVF process that impacts emotions.

What are the ethical concerns of gender selection?

Gender selection is highly controversial - many people are so strongly opposed to deliberately trying to conceive a boy or a girl for a range of reasons:

  • There are tough questions about what to do with discarded embryos not of the desired gender
  • Many people fear gender selection could become a "slippery slope" towards creating "designer babies"
  • Critics also say parents should not be inflicting specific notions of what gender means on their children, known as "gender imprinting"
  • Others argue it should only be done for medical, rather than social reasons of "family dynamic balancing"
  • Valuing one gender over another is fundamentally wrong to many
  • Religious people feel it is against God's will

In 2018, the UK's fertility regulator investigated claims fertility doctors might have helped couples choose the gender of their baby. It's illegal to do this in the UK unless there are clear medical reasons, like a family history of illnesses found only in boys or girls.

Sex versus gender

The issue of gender and how it relates to sex (female or male) is also controversial. Not everyone identifies with the gender they are assigned at birth. Opponents of "gender essentialism", the idea that males and females are fundamentally different, disagree with gender selection. They argue that your little boy or little girl may not always identify the same way.

"Gender imprinting", or enforcing cultural values, beliefs, norms and orientations associated with gender, is also a risk. Especially if the desired boy or girl does not behave in the way traditionally and culturally associated with their gender.

Whatever your child's genitals, their gender identity and gender expression may not match. For the purposes of this article, gender selection refers to the sex of your baby assigned at birth.

Medical gender selection controversies: discarded embryos

Whilst interfering with fertility at all is controversial within many religious circles, the main reason that medical gender selection is particularly frowned upon is the question of those discarded embryos. The process of medical gender selection involves creating several embryos using in vitro fertilisation (artificially joining egg and sperm in a lab) and then determining which are of the preferred gender. Which means that there will be some that are left over, or "abandoned". This also happens where couples undergoing IVF have been through several tries and can no longer pay to store their embryos. These are usually destroyed or they can be given to other couples, known as embryo adoption.

The slippery slope towards "designer babies"

Critics of gender selection suggest it's a way towards designing babies that suit your idea of what's desirable in terms of how a child looks, too. Screening already allows couples to abort babies that have genetic abnormalities and critics argue it might not be long until these methods allow parents to eliminate almost every difference that they don't like. Some clinics already allow you to predetermine eye and hair colour to match your preferred aesthetic.

Dr Gareth Nye told us, "There are ethical issues around selecting designer babies which has been around for 20 years or more. The problem with allowing one aspect like gender means there's no barrier to stop selections based on eye colour or hair colour or genetic size for example."

Natural methods for gender selection

Some parents might prefer to try natural methods for gender selection. Whilst the evidence for these methods is mixed, some come with varied success rates. Conception methods that rely on tracking ovulation claim a success rate of 70% plus so what's the evidence behind them? Why do parents try them?

Looking for a more balanced family dynamic

Author of the Babydust Method Kathryn Taylor, who supports natural ways to influence the gender of your baby, is not overly concerned by natural gender selection. She believes that natural ways to select gender at conception are relatively harmless.

She told us, "People are already controlling how and when they conceive and with IVF you can select against certain disabilities. Contraception allows you to control when you get pregnant. Altering the timing and frequency of sex to try for a boy or a girl is completely natural and it's not 100% effective. We're just helping people to gradually tip the scales towards a more balanced family dynamic."

Gender selection myths and Old Wives' Tales

Some Old Wives' tales for trying to conceive a boy or a girl might be fun to try, but there's absolutely no evidence they actually work.

Swipe to scroll horizontally
To conceive a boy To conceive a girl 
Eat more meat  Fish and vegetables should be on the menu 
Choose salty foods Eat chocolate and sweets 
Dads should drink carbonated drinks Spicy foods  
Make love at night Make love in the morning or afternoon 
Keep your man’s testicles warm Keep his pants cool! 
Have sex on odd days of the month Have sex on even days of the month 

However, some ideas behind natural gender selection do have limited scientific evidence backing them. The earliest ideas about gender selection with a scientific basis focus on timing of sex during the fertile window. Based on the work of Dr Shettles, the idea is that male and female sperm react differently once they're in the womb.

What are the theories behind how natural gender selection might work?

Dr Shettles, an obstetrician and gynaecologist, was the first to look into methods for trying to conceive a boy or a girl in the 1960s. His theories were the first to look at the make up of female vs male sperm and their behaviour. Shettles found differences in the shape and size of different sperm. However, Shettles was unable to know for certain which sperm were which, as DNA technology didn't exist back then to distinguish them.

What are the differences between male and female sperm?

Publishing his theory in his book, Your Baby’s Sex: Now You Can Choose (Amazon | £38),  Shettles believed male sperm preferred alkaline environments and female sperm liked acidic environments.

Shettles' theory:

  • male sperm have small, round heads
  • female sperm have larger, oval-shaped heads
  • female sperm live longer in the reproductive tract
  • Male sperm is faster and reaches the egg first, but they do not live as long

When should we have sex to conceive a boy or a girl?

After these discoveries, Shettles recommended that couples wanting to conceive a girl should not have sex too close to ovulation. This lets male sperm die and the female sperm wait for the egg.

Those who want a boy should have sex as close to ovulation as possible.

Dr Gareth Nye, who is an expert in maternal and fetal health at the University of Chester, told us, "Despite being around for 60 years, the medical evidence still isn't strong enough to prove Shettles' method. Past studies suggested a big difference between X and Y sperm, however, recent studies suggest only negligible differences. When studying ratio, shape and size, motility and swimming pattern; strength, electric charge, pH, stress response, etc, the only difference between X and Y sperm is in their DNA content."

The Babydust Method for gender selection

Kathryn Taylor, a microbiologist and mum who wanted to select the gender of her babies, disagrees with Dr Nye. Her book on how to conceive a baby boy or girl is very popular and sells thousands of copies every month, all across the world. Having done lots of research into Shettles' method and his original theory, her tweaked version claims a 87% success rate. Kathryn is confident that gender selection is not only plausible, but likely if you follow her method.

The timing is right: sex on the schedule

Though her method differs from Shettles' original, it relies on timing and frequency. For example, she recommends couples trying to conceive a girl should only have sex once a month, 2-3 days before ovulation. She recommends women should strictly track ovulation. Ovulation tracking (working out when your egg will be released) wasn't as straightforward in the 1960s, but women are now able to do so easily with ovulation monitors and urine sticks (ClearBlue Ovulation Kit, from Boots | £36.99).

Kathryn Taylor, author of the method, told us "There are a lot of ways people try to choose the gender of their baby but the Babydust method has been successful for so many. Our anecdotal data collection suggests it's about 87% of couples trying who get the gender baby they want. The diet and PH part of the Shettles method has never been proven, which is why I focused on honing the timing and frequency of when couples should have sex."

Key timing tips for natural gender selection

The evidence for natural methods for gender selection is limited and weak. Studies found no effect from these conception methods.

If you want to try and "sway" your baby's gender, the basic advice is:

To conceive a boy

  • Have sex close to ovulation as possible. The theory is that male sperm are fastest to the egg but don't live very long. This should be easiest to do if you are tracking ovulation with urine strips.

To conceive a girl

  • Have sex two to three days before your predicted ovulation day. You may have to track for a few months as this is harder to predict than having sex on the day of ovulation if you are tracking it with urine strips.

How common is trying to select your baby's gender with natural methods?

Microbiologist and author of the Babydust method, Kathryn Taylor, says that natural gender selection is rising in popularity. Her book, has sold millions of copies. She also has a Facebook community of  50,000+ members. She says trying for a little girl is most common. About 2:1 of women are wanting to have a girl in their next pregnancy.

"It's not always easy to try and abide by our methods. Sometimes people get overtaken by the moment or life gets in the way of conceiving. . It's a taboo subject, as is gender disappointment when an attempt doesn't work out. Don't take it too seriously and plan your future around conceiving a boy or a girl." - Kathryn Taylor

Christie, a mum of four got the girl she was hoping for. She said that following the theories was quite easy and only took her a few cycles.

"I'd seen the Shettles method mentioned somewhere on a Facebook group and it intrigued me. Whilst I really did not mind what sex baby we had, I thought it might be nice to give it a go. So we looked into it, just some very basic Google searches. I didn't want to change diet or anything. But we decided to follow the timing for sex before ovulation.  - Christie, who got the girl she wanted.

Dealing with gender disappointment after failed gender selection

Whatever your view of deliberately trying to conceive a boy or a girl, it's important not to put too much importance into what genitals your baby has. Whilst gender disappointment is more common in some Asian countries (and a risk for abortion for reasons of gender), it can affect couples of any nationality. If you're experiencing gender disappointment during your pregnancy, speak to your midwife for support. Anecdotally, most people find that it fades soon after your baby is born and you begin to get to know your new family member.

Dr Nye told us, "Essentially it boils down to a roughly 50/50 chance of having a boy or girl. Those who believe one method or another often remember it when it works or forget if it doesn't. Until someone collects the clear data from couples at conception and birth, we won't know for sure which methods are more effective."

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Tannice Hemming
Maternity and family writer

Tannice Hemming has worked alongside her local NHS in Kent and Medway since she became a parent and is now a mum of three. As a Maternity Voices Partnership Chair, she bridged the gap between service users (birthing women and people, plus their families) and clinicians, to co-produce improvements in Maternity care. She has also worked as a breastfeeding peer supporter. After founding the Keep Kent Breastfeeding campaign, she regularly appears on KMTV, giving her views and advice on subjects as varied as vaccinations, infant feeding and current affairs affecting families. Two of her proudest achievements include Co-authoring Health Education England’s E-learning on Trauma Informed Care and the Kent and Medway Bump, Birth and Beyond maternity website.