A baby's biological sex is determined at conception by chromosomes (XX for female, XY for male), but the physical sex organs begin differentiation around weeks 6 to 9, with male development starting first due to the Y chromosome's SRY gene triggering testosterone production, while female organs develop later without these signals. You can usually see distinct anatomy via ultrasound around 18-22 weeks, though early glimpses might be possible by 11-13 weeks, and genetic blood tests can reveal sex as early as 10 weeks.
Ultrasound Scan
By week 14, a baby's gender may be revealed via ultrasound. However, an ultrasound technician might have difficulty distinguishing between a boy or a girl at this point. Doctors generally recommend waiting until weeks 19-20 to have your anatomy scan ultrasound in order to show the correct gender.
Although the formation of the fetus's gender occurs from the moment the egg and sperm meet, it is not until the 9th week of pregnancy that the fetus's genital organs develop differently, allowing detection via ultrasound from the 12th week onwards.
The accuracy of determining your baby's gender increases with how far along you are in the pregnancy. The accuracy can vary from 70.3% at 11 weeks to 98.7% at 12 weeks, and 100% at 13 weeks. Eleven weeks is the earliest that sex determination can be carried out with an ultrasound using a method called the 'nub theory'.
Can the Gender of Baby Change During Pregnancy? Sex determination of a baby happens during fertilization, and it can't change during your pregnancy. However, there's a slim chance that the provider could read the 20-week ultrasound incorrectly and tell you you're having a girl (or a boy) when the opposite is true.
But do these cravings really predict baby's sex? Scientific studies, including the comprehensive review by Wolfson & Bleich, have found no consistent pattern linking specific cravings to fetal sex.
We tend to overpredict boys more often than girls.
This can happen, for example, if the baby is developing slowly and the tubercle hasn't begun to point up or the umbilical cord is mistaken for a penis. While gender prediction is much more accurate during the 20-week ultrasound, there's still a chance it can be wrong.
But in this study, women who had higher blood pressure and other signs of physical stress had four boys for every nine girls (ratio 4:9); while moms who were psychologically stressed had two boys for every 3 girls (ratio 2:3). All of the women had healthy pregnancies.
Women who have had multiple children of the same sex are more likely to have another baby of the same sex, a new study has found. Maternal age and genetics could be 'weighting the coin toss' for some couples, rather than every child having a truly random 50/50 chance of being a boy or a girl.
Yes, you can sometimes find out the baby's sex at 12 weeks using specialized ultrasound techniques like nub theory, with studies showing accuracy rates from 70% to over 90%, but it's not definitive; Noninvasive Prenatal Testing (NIPT) blood tests are more accurate (as early as 9-10 weeks), and the standard anatomy scan around 18-22 weeks offers clearer results for general ultrasound.
Whether your baby is a boy or a girl is determined by the chromosome it inherits from its father. The egg from its mother always contains an X (female) chromosome, but the sperm contains either an X (female) or a Y (male) chromosome.
Couples can improve their chances of having a baby boy by conceiving in the autumn, while those who want a girl should try to conceive in spring, claims a study in the Human reproduction journal.
What are the 3 lines on an ultrasound? The 3 lines are the image you can see on the scan of a baby girl's genitals: the clitoris, surrounded by the 2 lips of the labia. So if there are 3 lines on your pregnancy scan, you're pregnant with a little girl.
Children begin to understand and express their gender identity early in life. They may express their gender through their choices in clothing, social relationships with peers, choice of toys, or preferred nicknames.
Here, using data from 740 British women who were unaware of their foetus's gender, we show that foetal sex is associated with maternal diet at conception. Fifty six per cent of women in the highest third of preconceptional energy intake bore boys, compared with 45% in the lowest third.
There isn't strong evidence that morning sickness starts earlier if you are pregnant with a boy. Most research shows that the timing of morning sickness is similar regardless of whether you have a boy or a girl.
The study found that maternal age played a key role in children's sex at birth. Women who began having children over age 28 were slightly more likely to have either all boys or all girls. Chavarro said these differences could be due to biological changes in women as they age.
“The theory is that the X chromosome is bigger and heavier than the Y chromosome, so the Y-chromosome sperm swim faster,” explains Twogood. “X-containing sperm are more tenacious, so having intercourse longer before ovulation will more likely result in a female-sex fetus.”
Your biological father can pass on physical traits such as your biological sex, eye color, height, puberty timing, fat distribution, dimples, and even risk factors for certain health conditions.
The truth is, individual variations in pregnancy symptoms and hormones affect everyone differently, regardless of the baby's sex. Pregnancy is an exciting time, and it can be fun to guess the gender of your baby.
When you shout at a pregnant woman: ⚠️ Her stress levels go up ⚠️ Her blood pressure can rise ⚠️ It can affect the baby's growth and brain development ⚠️ In some cases, it may even lead to early labor 💬 Kindness, calm, and support are not just good for her - they're good for the baby too. 👩⚕️ Speak gently.
Sports and activities to avoid while pregnant
Any competitive sports where you have to move your body in a way that may not be safe. Activities with unsafe environments — such as spas, hydrotherapy pools or 'hot' yoga. Activities that involve heavy equipment — such as weightlifting, skiing and scuba diving.
23 signs you're having a boy
7 months pregnant is 28 weeks pregnant. The seventh month of pregnancy spans approximately weeks 25 through 28.
You must ensure you are at least 6 weeks pregnant at the time of taking the test, ideally waiting until 8-10 weeks. If you take the test too early, there will not be enough DNA in your blood sample from the baby to analyse and ascertain the gender.