News ID: 236418
Published: 0531 GMT December 25, 2018

Why are more boys than girls born every single year?

Why are more boys than girls born every single year?

Every year, there are always more baby boys than girls born in England and Wales. Fact. Why?

Since records began in 1838, the cries of babies born every year have been predominately male, BBC wrote.

In not one year, stretching back to the start of Queen Victoria's reign, have girls outnumbered boys at birth.

In 2017, in England and Wales, for example, there were 348,071 live male births and 331,035 live female births —    a difference of roughly 17,000.

And that higher tally of males compared to females born each year is a pattern that has repeated itself for nearly 180 years.

In fact, a ratio of roughly 105 male births for every 100 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.


More surprisingly, it is a ratio that has been known about since the 17th Century.

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.

"At every age, in almost every time and place, a man is more likely to die than a woman," said Prof. David Steinsaltz, associate professor of statistics at the University of Oxford.

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 fertilize the woman's egg.

These include the ages of the parents, the woman's ovulation cycle, levels of stress and diet.

There is 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 there are equal numbers of female and male-producing sperm and roughly equal numbers of conceptions, then more female fetuses 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 fetuses are more fragile later in pregnancy and lead to more stillbirths.

Scientists say it is hard to pin down what actually happens and the reasons why.

What we do know is that more male conceptions reach term and more boys are born.


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