The mid-parental method adds the parents' heights, adds 13 cm for boys (subtracts 13 cm for girls), and divides by two. The result is the target height — the average adult height your child is most likely to reach. Because genetics is a lottery, we also show a 68% range (±5 cm) and a 90% range (±8.5 cm): most children finish somewhere inside the wider band. About 5% of children finish outside even that.
双亲身高法：父母身高相加，男孩 +13cm、女孩 −13cm，再除以 2。结果是靶身高——孩子成年后最可能达到的平均身高。由于遗传是抽签，我们还给出 68% 范围（±5cm）与 90% 范围（±8.5cm）：多数孩子落在较宽区间内，约 5% 的孩子甚至落在其外。
Frequently Asked Questions
How accurate is the mid-parental height method?
It's the standard screening tool used in pediatric clinics. On average it's accurate to within a few centimeters, but individual results vary — treat the 90% range as your real expectation.
这是儿科门诊常用的标准筛查方法。平均误差在几厘米以内，但个体差异存在——请以 90% 区间作为真实预期。
Can nutrition change the predicted height?
Yes. Chronic malnutrition in childhood can subtract several centimeters, while good nutrition, sleep and activity help a child reach (but rarely exceed) the genetic range.
可以。童年期长期营养不良可能让最终身高缩水数厘米，而良好的营养、睡眠与运动帮助孩子达到（但很少超过）遗传范围。
When can we predict height more precisely?
Around age 2 you can double a toddler's height for a rough estimate; the bone-age X-ray method (around age 9–14) is the most accurate clinical tool.
两岁左右可用"两岁身高 ×2"粗略估算；骨龄 X 光法（约 9–14 岁）是最准确的临床工具。
