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Comment by version_five | Hacker News Reader

See the chart linked below (third image, after two of the PIs)

https://news.iu.edu/live/news/28109-study-reveals-average-ag...

  the average age that humans had children throughout the past 250,000 years is 26.9. Furthermore, fathers were consistently older, at 30.7 years on average, than mothers, at 23.2 years on average, but the age gap has shrunk in the past 5,000 years, with the study’s most recent estimates of maternal age averaging 26.4 years. The shrinking gap seems to largely be due to mothers having children at older ages.

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I mean, wouldn't you expect a gap in those numbers, purely from a biological perspective? If there's a biological cap on how old a woman can be and give birth, but there's no cap on how old a man can be and father a child, unless there's some truly odd stuff going on it seems obvious that this gap would exist. They even say that the shrinking of the gap over time is largely because of women having children early, not anything changing in men.

This is part of it. Teen births are way down and women are delaying having kids until their 30s. But also, importantly, women are starting to earn at parity or out earn men, negating the need for a partner to support themselves. This is a cause of the imbalance I believe. The pool of potential female partners wasn’t great before for the age cohort, and empowered women shrink it further.

Also, men will date down, women typically don’t. So these higher earning, ambitious women are unable to find a partner that meets their expectations. Men are happy to (or if not happy to, can make do) exit the dating marketplace when this expectation mismatch occurs. There just aren’t enough women who want a low status low earning male partner.

Seems surprisingly late in life for pre industrial humans. But I guess they had more DNA samples from recent centuries.

And doesnt this say that the average maternal age was 23/patenal 30--not the "average age of first child" which would be lower. The average age of first child for women is now over 30 in the us i think. So the difference is huge.

(edit: corrected below)

> The average age of first child for women is now over 30 in the us i think.

Less handwaving, more cites[1].

[1] https://www.cdc.gov/nchs/nsfg/key_statistics/b.htm#agefb

I'd like to commend you for adding actual data here! Really helps the discussion :)

Depends on which cohort you look at. For college-educated women, that age is closer to 30:

https://www.pewresearch.org/fact-tank/2015/01/15/for-most-hi....

Similar breakdown in red states vs blue states. Blue states have much older age of first child, on average (because of correlation with educational attainment).

In fact the gap we should talk about is the gap between college-educated women and the rest (which stands at ~8 years)

yes thank you, i mixed up some things. the average age of giving birth is now 30 (https://www.nbcnews.com/news/amp/rcna27827) which is (i think) the number being measured in the paper as 23 historically. So the increase is large. Also I am somewhat confused because other sources like the NYT from 2018 say the first birth number is 26...i wonder if the statistics you provided are skewed by younger motherhood for the older part of the 15-44 cohort? Here you can see in many cities the avg age of first birth IS 30+. The big divide is geographical and by college degree. These are 2018 numbers so it wouldve probably gone up a bit more since then (https://www.nytimes.com/interactive/2018/08/04/upshot/up-bir...)

it would also be interesting to see recent statistics on foreign born mothers vs us born mothers...here is another source supporting that first motherhood is now 26+, not 23 as in cdc numbers:https://www.pewresearch.org/fact-tank/2018/06/28/u-s-women-a...

one last source for 26+ for first birth already in 2014: https://www.cdc.gov/nchs/products/databriefs/db232.htm

the original cdc numbers cited are perhaps not best way to look at the matter, because they include women who were giving birth in 80s and 90s.

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