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  • Most parents-to-be assumed that the sex of their child comes down to a flip of the chromosomal coin, with an equal chance at having a boy or girl.


  • But in reality, the odds aren't even.


  • For every 100 girls born, the world gains about 106 baby boys.

    每當有 100 個女孩出生時,相對會有 106 個男孩出生。

  • Currently that skewed sex ratio comes out to roughly ten million more baby boys than girls born worldwide each year.

    目前這樣失衡的性別比例,造成全球每年出生的男嬰比女嬰多出約 1,000 萬個。

  • There are some countries where human meddling stacks the odds even higher in favor of boys.


  • But that doesn't explain the fixed odds everywhere else.


  • The intrinsic boy-girl ratio is rigged by mother nature.


  • In fact, it's even more rigged than birth rates show.


  • Human conception results in about 150 male zygotes for every 100 females.

    人體受孕的結果大約是 150 個男性受精卵比上 100 個女性。

  • But there's a rather tragic reason for this big biological boy bias early on.


  • Male fetuses are much more likely to be miscarried or stillborn than female fetuses.


  • And boys that do make it out of the womb suffer more fatal diseases, take more mortal risks and fall prey to more violence than girls.


  • So by the time kids grow up and reach baby-making age, the ratio of males to females is just about one to one.


  • But the likelihood of a boy even making it to birth is also influenced by his mom's living conditions during pregnancy.


  • For example, when a massive famine struck China in the 1960s, the relative likelihood of having a son suddenly dropped until the famine ended.

    例如,中國在 1960 年代發生大饑荒,男孩的出生率急劇下降,直到饑荒結束才恢復。

  • And male Americans born to billionaires seem to have higher than average odds of fathering sons.


  • Somehow, female biology suppresses boys' survival in the womb during tough times, and boost it when times are good.


  • We've seen same pattern in other mammals too.


  • When resources are scarce, mothers give birth to fewer males than normal.


  • When resources are plentiful, they bear more.


  • The best explanation we have for this has to do with sex -- the other kind


  • In biological terms, the whole goal of copulation is to reproduce to pass on your genes to someone who will someday pass them on again.


  • Female offspring are almost guaranteed to reproduce, famine or no famine because male mammals are pretty much always willing to mate.


  • Males on the other hand have to compete for mating privileges.


  • A well-nurtured hunk has a good chance of mating with lots of females.


  • While a male weakened by famine might not score at all.


  • Some male offspring are a bigger risk in general. At all stages they're more likely to die.


  • And even if they live they might not reproduce.


  • But when times are good, boys' potential to father lots and lots of babies make them a biological risk worth taking.


  • Thanks to everyone who support us on Subbable.

    謝謝大家支持 Subbable。

  • Without you we literally couldn't continue to make these videos.


  • If you aren't yet a supporter of MinuteEarth and want to become one, head over to to make a one-time or monthly pledged support and thanks for watching.

    如果你還不是 MinuteEarth 的支持者,而你想成為支持者的話,去 並且做單次或每月的支持吧!謝謝收看。

Most parents-to-be assumed that the sex of their child comes down to a flip of the chromosomal coin, with an equal chance at having a boy or girl.


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B1 中級 中文 美國腔 男性 男孩 機率 饑荒 男女 女性

天啊!世界上的男生比女生多的原因竟然是... (Why Do We Have More Boys Than Girls?)

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    Gisele Sung 發佈於 2020 年 11 月 10 日