Girl to boy birth ratio uk
Across the world there are differences in the sex ratio at different life stages. This imbalance in the male and female population can in some cases be traced back to birth: in some countries the number of boys and girls born each year is significantly skewed. In the map we see the differences in sex ratio at birth across the world. Here the sex ratio is measured as the number of male births for every female births; a value greater than indicates there are more boys than girls born that year. A figure of would indicate that there are male births for every female births. The first striking point is that in every single country of the world there are more boys born than girls.SEE VIDEO BY TOPIC: Top 10 countries with a shortage of men
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List of countries by sex ratio
These are external links and will open in a new window. Every year, there are always more baby boys than girls born in England and Wales. In not one year, stretching back to the start of Queen Victoria's reign, have girls outnumbered boys at birth. In , in England and Wales, for example, there were , live male births and , live female births - a difference of roughly 17, And that higher tally of males compared to females born each year is a pattern that has repeated itself for nearly years.
In fact, a ratio of roughly male births for every female ones is generally seen as natural and normal. It is fairly consistent around the world, although in some countries like China and India the gap is wider because male offspring are more desirable. But why this ratio exists is not yet completely understood - although there are several theories.
The first theory is an evolutionary one which says that in order to have an equal number of males and female in adulthood, there have to be slightly more males born. That is because being a male is a dangerous thing. Males are more likely than females to die in childhood and at all stages of life - from accidents, taking risks, suicide and from health problems. So more males than females at the start of life should mean equal numbers of men and women in adulthood, so the theory goes.
In fact, adult women always end up slightly outnumbering adult men in the UK, according to Office for National Statistics figures - and living longer. There are lots of different factors that could determine whether a male sperm carrying a Y chromosome or a female sperm carrying an X chromosome is first in the race to fertilise the woman's egg.
These include the ages of the parents, the woman's ovulation cycle, levels of stress, diet and sexual position. One popular theory is that the odds of having a girl increase by having sex several days before ovulation and then abstaining so that the female sperm, which live longer, but swim more slowly than male sperm, outlast their counterparts.
Conversely, if sex happens closer to ovulation or after it, the best swimmers get to the egg first and boys are produced. Parents may swear by these techniques, but scientists say there is little evidence they make any difference.
There is also some research which suggests parental stress could lead to the birth of more girls, while living through wars and conflicts may give rise to more male conceptions. If planning that sexual encounter does not have an impact on a baby's sex, then could something else be happening during pregnancy? If there are equal numbers of female and male-producing sperm and roughly equal numbers of conceptions, then more female foetuses must perish to give males the upper hand.
Some research suggests females are more likely to be lost in the womb during early pregnancy, but other studies have shown males foetuses are more fragile later in pregnancy and lead to more stillbirths. Why are more boys than girls born every single year?
Image copyright Getty Images Image caption There are normally around male births for every female ones Every year, there are always more baby boys than girls born in England and Wales. Since records began in , the cries of babies born every year have been predominately male. More on this story.
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Human sex ratio
Research over hundreds of years has consistently found that boys naturally outnumber girls at birth. This increase in the sex ratio is driven largely by births in China, where sex ratios have declined slightly in recent years but remain the highest in the world. However, disproportionately large shares of baby boys are found in other countries scattered throughout Asia and the Caucasus, as well. Azerbaijan, Armenia, Georgia, South Korea, and the Solomon Islands round out the list of places with the highest sex ratios. India is tied with Macedonia, Montenegro, Papua New Guinea, Samoa, Serbia and Suriname for 7th place, with a ratio of boys born for every girls.
These are external links and will open in a new window. Every year, there are always more baby boys than girls born in England and Wales. In not one year, stretching back to the start of Queen Victoria's reign, have girls outnumbered boys at birth. In , in England and Wales, for example, there were , live male births and , live female births - a difference of roughly 17,
Sex ratios at birth: statistics
The human sex ratio is the number of males for each female in a population. This is a list of sex ratios by country or region. The table's data is derived from The World Factbook ,  except when otherwise indicated. It shows the male to female sex ratio as estimated by the United States' Central Intelligence Agency. However, there are differences between the estimates by The World Factbook and numbers reported by the census offices of respective countries. For example, The World Factbook in reported Switzerland's sex ratio at birth as 1. A ratio above 1, e.
Why are more boys than girls born every single year?
Sex ratio at birth (male births per female births)
The odds that you will give birth to a boy or girl depend on where in the world you live