The most accurate way to know if you're having a boy or girl is an ultrasound, often done at around 20 weeks.
Male fetuses are more fragile and are statistically less likely to be conceived or survive pregnancy when food is in short supply. Female sperm are more robust and baby girls are hardier early in pregnancy, so in leaner times they may be more able to survive.
Women carrying a male fetus have significantly increased maternal weight gain during pregnancy when compared to women with a female fetus. The increased sex ratio remains when adjusting for each newborn weight group.
Conclusion: Despite numerous prior studies derived from small samples failing to reveal significant sex differences in fetal activity, the present study demonstrates that males are about 10% more active than females during the latter two-thirds of pregnancy and are even more so following birth.
Nature is designed to favour the conception of boys from September to November and girls from March to May because of an evolutionary mechanism aimed at keeping the overall sex ratio as near to 50:50 as possible, the scientists said.
Because male sperm is the faster of the two, Shettles suggests having intercourse as close to ovulation as possible, so the male y sperm can reach the egg first. If you have sex several days before the day of ovulation, the less resilient male sperm may die off. This leaves more female sperm to fertilize the ovum (5).
A recent study suggests that carrying a male or female foetus could lead to different immune responses in pregnant women. Pregnant women carrying girls have a greater chance of experiencing nausea and fatigue, according to the results of a study from the USA's Ohio State University Wexner Medical Center.
The ratio of male to female births, called the sex ratio, is about 105 to 100, according to the World Health Organization (WHO). This means about 51% of deliveries result in a baby boy.
The only way to guarantee a boy or girl? Currently, the only way to guarantee sex is a technique called preimplantation genetic diagnosis (PGD), where a single sperm is implanted in the egg in a type of in vitro fertilization called ICSI (intracytoplasmic sperm injection).
Which parent genetically determines the gender (sex) of a baby? Neither parent is fully responsible for determining the sex of the baby. However, all eggs produced by the female have an X sex chromosome, and all sperm from the male have either an X or Y chromosome.
All human individuals—whether they have an XX, an XY, or an atypical sex chromosome combination—begin development from the same starting point. During early development the gonads of the fetus remain undifferentiated; that is, all fetal genitalia are the same and are phenotypically female.
Speed: since sperm containing the Y chromosome are faster than those containing the X chromosome, if the egg is in the fallopian tube at the time of intercourse, there is a greater probability of a Y sperm reaching and fertilising it, which means there is a greater probability of the baby being a boy.
A study published in the Proceeding of the Royal Society B found that women with diets high in potassium (found in bananas, as well as potatoes, clams, and artichokes, among other foods) are more likely to bear sons.
Researchers surveyed 740 women during their first pregnancy and found that those with a diet high in potassium (one of the main vitamins in bananas) were more likely to have a boy.
Or that if you feel your baby moving more on the right side, then you're probably having a boy. But there's no evidence that there's a difference between the movements of boys and girls in the womb (Medina et al 2003).
Research shows girls kick as often as boys. Babies who kick a lot in the womb are also more active after birth. Some mothers have more trouble feeling the kicks than others. If the placenta is on the front side of the womb, or if you are overweight, you will feel the kicks less.
Many women choose to delay announcing a pregnancy at least until the end of the first trimester (12 weeks into their pregnancy). This is usually because of concerns about the risk of miscarriage (pregnancy loss) during this time.
Therefore, timing intercourse as closely to ovulation as possible means you will have a better chance of conceiving a boy, because a healthy male sperm cell will probably reach the egg first.
While historically, there have been about 105 boys born for every 100 girls worldwide — which creates a “sex ratio at birth” of 1.05 — the share of boy babies has increased in recent decades. 2011 data from the World Bank show the global sex ratio at birth is now 1.07, or 107 boys born for every 100 girls.