這個公式能幫你預測你家孩子身高
Would you like to know if your child is set to stand head and shoulders above the rest? Or if they're likely to stay diminutive into adulthood?
想知道你家孩子將來的身高會鶴立雞羣嗎？還是會一直這麼矮下去？
There is an easy (although fallible) mathematical equation that can help you predict how tall your child will be.
有一個簡單（但不一定靠譜）的數學公式可以幫你預測孩子未來的身高。
The formula, which has been used since the 1970s and was revealed in the New York Times, predicts that 'most (but not all) children will reach a height somewhere within a fairly small range that can be estimated by the average combined heights of their parents.'
該公式自上世紀70年代開始流行，發端於《紐約時報》。公式稱，“根據父母的平均身高總和，可以推算出孩子身高的波動範圍，這個波動範圍很小。大部分（並非所有）孩子適用這個規律。”
How does it work?
具體怎麼算呢？
BOYS
男孩
Add the heights of both parents plus 5in (13cm) and divide by two.
父母身高相加，總和再加5英寸（13釐米），用結果除以2。
GIRLS
女孩
Add the heights of both parents minus 5in (13cm) and divide by two.
父母身高相加，總和減去5英寸（13釐米），用結果除以2。
There is a more complicated formula for extreme differences in parental height.
父母身高差距比較大的話，需要用另一個複雜點兒的公式。
These predictions are by no means completely reliable, however, as environmental factors such as nutrition play a big part in determining human height.
不過這種預測不可能完全準確，因爲還要考慮環境因素，比如營養狀況就會對身高發揮重要影響。
Genetics is estimated to account for between 60 and 80 per cent of one's final height.
基因約佔所有影響身高因素的60%至80%。
A study of 8,798 pairs of Finnish twins conducted in 2000 found that genetics accounted for 78 per cent of height in adult men and around 75 per cent in women.
2000年，一項針對8798對芬蘭雙胞胎的研究顯示，基因對男性身高的影響達78%，對女性達75%。
However, as we all know not all children born to the same couple will be the same height.
不過正如我們所知，同一對父母，其所有孩子的身高不一定會是相同的。
Science shows that height tends to decrease in younger siblings.
科學研究證明，後出生的孩子身高會傾向於變矮。
Another popular method for predicting height is to double a boy's height at age two or a girl's height at 18 months.
另一個著名的預測未來身高的方法是：男孩兩歲時的身高乘以2；女孩18個月時的身高乘以2。
Most children will reach an adult height within 4in (10cm) of this estimation.
大部分孩子長大後的身高會在這個預估數值的上下4英寸（10釐米）範圍內波動。
