# Ideal Age for becoming a Mother? **URL:** \ **Category:** Factual Questions\ **Created:** [December 29, 2011, 9:54pm UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762 "2011-12-29T21:54:29Z")\ **Posts on this page:** 14\ **Page:** 3
**Author:** ![drtj](https://avatars.discourse-cdn.com/v4/letter/d/9dc877/32.png) [@drtj](https://boards.straightdope.com/u/drtj)\ **Post date:** [December 31, 2011, 7:02pm UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/41 "2011-12-31T19:02:44Z")
This is actually a very interesting and important question. The age of puberty has been going steadily down in the US over the past 100 years while the common age of marriage and child bearing has been going up. Also, we now know that fertility starts to decrease in the early twenties. This combined with earlier sexual activity presents several social problems including teen moms and fertility problems among older women. While late teens and early twenties may be the most fertile time for a mother, it may not be the best time in terms of social roles. So, a women in her late 20s and early 30s may be better prepared socially and psychologically be be a mother, she may not be as fertile. > **[Report\_The-Falling-Age-of-Puberty\_August\_2007.pdf](https://www.bcpp.org/wp-content/uploads/2017/03/Report_The-Falling-Age-of-Puberty_August_2007.pdf)** > > 1291.23 KB ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [December 31, 2011, 7:56pm UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/42 "2011-12-31T19:56:12Z")
> [@zombywoof](#): > > If we’re talking about things from a purely evolutionary standpoint, if ~18-20 is the ideal age, then why have evolutionary pressures not delayed menarche until then? If girls become fertile at ~12-13, isn’t that because genes for fertility at that age have been succesfully handed down over many generations? Girls become fertile now at that age because of better nutrition, but they didn’t do so during most of our evolutionary past. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [December 31, 2011, 8:13pm UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/43 "2011-12-31T20:13:52Z")
> [@drtj](#): > > [http://www.breastcancerfund.org/assets/pdfs/publications/falling-age-of-puberty.pdf](http://www.breastcancerfund.org/assets/pdfs/publications/falling-age-of-puberty.pdf) note the article also has the quick mention and graph that average age on menarche onset (first period) was 17 or 16.5 about 1850 in Europe. This suggests that births before age 17 were not the norm until the 1900’s. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [December 31, 2011, 8:16pm UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/44 "2011-12-31T20:16:38Z")
> [@Wendell\_Wagner](#): > > Really Not All That Bright, nothing in the statistics in the post that you linked to nor in the link in that post answered the question that I asked. This question is the following: Over the past fifty or so years (in the U.S.), what has the (per capita) number of births to unmarried teenage mothers been for each year? By the (per capita) number, I mean that I don’t want to just know the raw number of births to unmarried teenage mothers in each year. If you tell me that the raw number of births to unmarried teenage mothers in 1961 was 892,274 and the raw number of births to unmarried teenage mothers in 2011 was 899,381 and then say that this proves that it’s going up, my reply will be that the population was considerably greater in 2011 than in 1961, so you would expect the number to go up. I can’t find numbers for the past fifty years. Will the past [twenty](http://www.childtrendsdatabank.org/sites/default/files/13_Fig03.jpg) do? ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [December 31, 2011, 8:17pm UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/45 "2011-12-31T20:17:54Z")
> [@md2000](#): > > note the article also has the quick mention and graph that average age on menarche onset (first period) was 17 or 16.5 about 1850 in Europe. This suggests that births before age 17 were not the norm until the 1900’s. No, it doesn’t. You’d need to look at the average age of menarche in traditional, h/g societies. Something that would be hard to do. It has been noted that agriculture improved the quantity of foods available, but not the quality. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [December 31, 2011, 9:39pm UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/46 "2011-12-31T21:39:55Z")
Another interesting datum: Isabella of Angoulême - b. 1188 (date may be in dispute) M. 1200 to King John of England, first child born 1207, 4 more followed not long after; despite stories that the king was infatuated with her and would stay in bed with her until noon sometimes, no children for 7 years until she was 19 and then 5 with John, then 9 more with her next husband. Yet she was a noble; if the question is quality of diet, she would have one of the better diets. This suggests that her fertility did not start until late teen years. Since, yes, we can’t determine what the situation was in early H&G times, we can get a sense of where it might have been from this sort of early data. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [December 31, 2011, 10:30pm UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/47 "2011-12-31T22:30:32Z")
> [@md2000](#): > > Another interesting datum: > > Isabella of Angoulême - b. 1188 (date may be in dispute) M. 1200 to King John of England, first child born 1207, 4 more followed not long after; despite stories that the king was infatuated with her and would stay in bed with her until noon sometimes, no children for 7 years until she was 19 and then 5 with John, then 9 more with her next husband. Yet she was a noble; if the question is quality of diet, she would have one of the better diets. This suggests that her fertility did not start until late teen years. > > Since, yes, we can’t determine what the situation was in early H&G times, we can get a sense of where it might have been from this sort of early data. Not really. Few, if any, h/g girls would have eaten like royalty. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [December 31, 2011, 10:55pm UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/48 "2011-12-31T22:55:21Z")
> [@John\_Mace](#): > > Not really. Few, if any, h/g girls would have eaten like royalty. Not sure what you mean. The argument I thought I saw was that typical agricultural age diet may not be up to HG standards of \*\*\*quality \*\*\*- assuming that in prehistoric, preagricultural times, HG activity took place in the rich, fertile areas not the marginal subsistence areas. If anyone would have gotten the right quality, in terms of say, fat and protein as well as carbs, in terms of variety and vitamins, this is maybe as good as it gets? Here we have a girl who ate fairly well we assume, married at 12 and seems to have only started being fertile at 18 despite several years of an active sex life. (as well as we can possibly determine these details). Once fertility started, it seemed to remain cosnsistent for decades. Is it possible that good diet is not the only driver of early puberty? Maybe infant diet (which may not have been as good) is another driver? Prenatal? Is the ideal HG diet much higher in meats and less so in vegetables/starch? Possibly, alternatively, she’s an outlier example? Who knows… ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [December 31, 2011, 10:59pm UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/49 "2011-12-31T22:59:43Z")
I’m sorry, Really Not All That Smart, but you’re still not giving me the statistic that I want (even ignoring the fact that the chart is only over the past twenty or so years). The chart that you’ve linked to says that the percentage of births to mothers 15 to 19 where the mother is unmarried (in the U.S.) has gone from 67.1% to 87.6% from 1990 to 2008. We’re all in agreement that the percentage of teenage mothers who are unmarried has gone up. We’re also all in agreement that the percentage of teenage women who have babies has gone down (in the U.S.). The statistic that I’m looking for is the raw number of births to unmarried women 15 to 19 in the U.S. over this time period. More specifically, I’m looking for the raw number of births to unmarried women 15 to 19 in the U.S. divided by the population of the U.S. (or, if it’s possible to find this, the raw number of births to women 15 to 19 divided by the the number of women 15 to 19 in the U.S.). Do you understand the difference between the statistic you’ve given me and what I want to see? ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [December 31, 2011, 11:03pm UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/50 "2011-12-31T23:03:06Z")
Yes, teacher. I’ll see what I can do- though you’ll have to wait until I sober up. Happy New Year! ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [December 31, 2011, 11:25pm UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/51 "2011-12-31T23:25:35Z")
> [@](#): > > The chart that you’ve linked to says that the percentage of births to mothers 15 to 19 where the mother is unmarried (in the U.S.) has gone from 67.1% to 87.6% from 1990 to 2008. This one has the best stats, a small graph: (1990 seems to be an odd year…) [http://www.guttmacher.org/pubs/tgr/05/1/gr050107.html](http://www.guttmacher.org/pubs/tgr/05/1/gr050107.html) So 67% of 60 per 1000 vs. 87% of about 48 per 1000 if I read the graph right. That`s 40.2 vs. 41.8 per 1000; that`s a marginal increase in unmarried mothers`births. Of course, the raw numbers would be larger difference, based on the fact that the 41.8 per 1000 represents todays larger population (of teenagers) compared to 1990. ---
**Author:** ![drtj](https://avatars.discourse-cdn.com/v4/letter/d/9dc877/32.png) [@drtj](https://boards.straightdope.com/u/drtj)\ **Post date:** [January 1, 2012, 12:48am UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/52 "2012-01-01T00:48:58Z")
I have a chart of the average age of menarche over the past 100 years in the US in a textbook at work. I’ll see if I can find it next week and post it. It has definitely gone down dramatically. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [January 1, 2012, 3:03am UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/53 "2012-01-01T03:03:38Z")
> [@md2000](#): > > Not sure what you mean.. I meant exactly what I said. H/Gs probably ate better than subsistence farmers (although it would probably have been all over the map), but it’s unlikely that many ate as well as a queen. ---
**Author:** ![rhubarbarin](https://avatars.discourse-cdn.com/v4/letter/r/eb9ed0/32.png) [@rhubarbarin](https://boards.straightdope.com/u/rhubarbarin)\ **Post date:** [January 1, 2012, 8:11pm UTC](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762/54 "2012-01-01T20:11:52Z")
> [@drtj](#): > > I have a chart of the average age of menarche over the past 100 years in the US in a textbook at work. I’ll see if I can find it next week and post it. It has definitely gone down dramatically. Yes, but unfortunately most of that older data was taken from girls living in asylums or working in mills in crowded, filthy cities with horrendous food. I am not surprised they didn’t get their periods until they were 17. We don’t have any data on 1900s farm girls or other more normal specimens. I think it’s more useful to compare modern American girls to the rafts of data we have on normal healthy girls elsewhere in the world, many of whom who eat very very differently than we do in this country. Well-nourished girls achieve menarche between 11 and 15, consistently, with a large majority having their first period between 12 and 14. [Previous page](https://boards.straightdope.com/t/ideal-age-for-becoming-a-mother/607762.md?page=2)