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When Can You Find Out the Gender (Sex) of Your Baby?

When and how you can find out your baby's sex, from blood tests at about 10 weeks to the mid-pregnancy scan, and how accurate each one is.

Before you use this guide: This is general educational information, not an individual medical assessment. We do not identify a clinician reviewer on this page, so please confirm personal health decisions with your doctor, midwife or paediatrician.

Many parents are curious about their baby's sex long before the birth. There are three main ways to find out, and they differ in timing and reliability. Whichever you choose, you do not have to find out at all. It is entirely your decision.

A quick summary

• A blood test (cell-free DNA, often called NIPT) can show the baby's sex from about 10 weeks, if the test is done and the result is shared.
• An early scan at 11 to 13 weeks can sometimes show the sex, but it is less reliable.
• The mid-pregnancy scan, at around 18 to 21 weeks, is when most parents find out.
• Otherwise, you will find out at birth.

Blood tests

Cell-free DNA tests analyse tiny fragments of the baby's DNA in the mother's blood. They are mainly used to screen for conditions such as Down's syndrome, and they can also detect the sex chromosomes. They can be done from around 10 weeks of pregnancy.

• In many countries, including the US, these tests are widely available, and the sex can be reported on request.
• In the NHS in the UK, they are usually offered only when an earlier screening result shows a higher chance of a condition. Private clinics offer them for a fee. Whether the sex is reported depends on the provider and local policy.
• A review of 90 studies found that they identified the sex correctly roughly 97 to 99 times in 100.
• Results can be affected by twin pregnancies, a lost twin, a very early test or unusual chromosome patterns.

Early scans (11 to 13 weeks)

Some sonographers can see the sex at the first-trimester scan, but it is less reliable than later. A review found that accuracy rose from about 69 per cent at 11 weeks to around 89 per cent at 12 weeks and 96 per cent at 13 weeks. Many clinics do not try to tell you the sex at this stage, because the baby is small and a wrong answer can be upsetting.

The mid-pregnancy scan (18 to 21 weeks)

The NHS says the scan is usually done between 18 and 21 weeks, and parents may be asked whether they would like to know the sex. In other places, such as the US, it is often done between 18 and 22 weeks. Its main job is to check the baby's development, but if the baby is in a good position, the sonographer can usually tell the sex. A review found that second-trimester accuracy is very high, with a median of about 99 per cent.

• The baby's position matters. If the legs are crossed or the baby's back is facing the probe, it may not be possible to see.
• Policies differ between hospitals and countries. Some do not tell you, so ask your midwife or sonographer in advance.
• In some countries, including India, it is illegal for providers to tell parents the sex of the baby before birth.
• Even when the answer is clear, no scan is perfect, so keep your plans flexible.

Tests for medical reasons

Amniocentesis and chorionic villus sampling (CVS) can also show the baby's sex, but they are offered only when there is a medical reason, because they carry a small risk of miscarriage. They are never done just to find out the sex.

Home blood-test kits and private scans

• Home kits that analyse a blood sample at a laboratory exist and can be used early in pregnancy. Their reliability depends on collecting the sample correctly, so treat the result as fun until it is confirmed.
• Private scan clinics offer early gender scans. Medical bodies generally advise keeping ultrasound to when it is useful, so choose a clinic with trained, registered sonographers.

What if I want a surprise?

Tell the sonographer at the start of the scan that you do not want to know. They will take care not to say or show anything. If you are asked about the test result and do not want to know, you can ask for the sex not to be reported.

What if I can't tell?

Sometimes a scan does not give a clear answer, and that is not a sign of a problem. A small number of babies are born with variations in sex characteristics, which can make the scan result less clear. If you have questions, ask your doctor or midwife.

A note on words

Scans and blood tests tell you about the baby's sex, based on anatomy or chromosomes. Gender identity is something your child will express as they grow. Many families use “gender” for the party and “sex” for the medical result, and either is fine.

Planning a party once you know? See our gender reveal ideas and our guide to planning a gender reveal party.

This content is for general information only and is not medical advice. Every pregnancy and every baby is different. Always talk to your doctor, midwife or paediatrician about your own situation, and seek urgent care if you are worried.