【美國生育率從 2.10 掉到 1.62 👶】
美國的總生育率在 2007 年見到高點 2.10，剛好踩在人口替代水準上，之後一路下滑，近年落在 1.62 附近。1976 年是 1.79，所以現在比五十年前的低點還低。
這個下滑最常見的兩種解釋都站不住。第一種說是青少年生育大幅減少拉低了數字。青少年生育率確實從 2007 年到近年下降約七成二，但研究推估它只能解釋總降幅的一到兩成多，其餘來自成年女性。第二種說是女性把生育往後延。研究發現三十歲以上的生育率並沒有相應補回來，減少最多的是第一胎，而且降幅最集中在二十歲出頭這一段。
少掉的不是晚點才生的孩子，是沒有發生的第一胎。這兩種情況對未來的勞動力和消費結構，推論完全不同。
規模上，美國近年的一般生育率比 2007 年低約兩成三，等於一年少了大約七十萬個新生兒。
數字本身要留一點餘地。這條線用的是聯合國的估計系列，顯示近五年大致持平；美國官方的出生統計則顯示 2025 年又創新低。兩邊的口徑和發布時程不同，2025 年的正式總生育率還沒有公布。
資料來源：聯合國人口司 World Population Prospects、美國國家衛生統計中心與相關學術研究（圖片來自 @Hedgeye）
US Fertility Has Fallen From 2.10 to 1.62
The US total fertility rate peaked at 2.10 in 2007, right at the replacement level, and has fallen since to around 1.62. The 1976 reading was 1.79, so it now sits below the low point of fifty years ago.
The two most common explanations do not hold up. The first is that collapsing teen births pulled the number down. Teen birth rates did fall about 72% between 2007 and recent years, but research attributes only somewhere between a tenth and a quarter of the total decline to them. The rest comes from adult women. The second is that women are simply having children later. Birth rates for women in their thirties have not risen to compensate, and what has fallen most is first births, concentrated among women in their early twenties.
What is missing is not a delayed child. It is a first child that does not happen. Those two cases imply very different things for the future workforce and for consumption.
On scale, the recent US general fertility rate is about 23% below 2007, which works out at roughly 700,000 fewer births a year.
The figure deserves some room. The series shown here is a United Nations estimate, which has been roughly flat for five years, while US vital statistics show births reaching another record low in 2025. The two differ in method and in timing, and the official 2025 total fertility rate has not been published.
Source: UN Population Division World Population Prospects, the US National Center for Health Statistics and related academic research (Image: @Hedgeye)