Notes about twin births

Some quick tidbits about twin birth because it’s yet another factor in the current birth trends and relative robustness of fertility in college moms.

  • Twin birth was around 10 per thousand births for white women and 12 per thousand for black women in 1940 and this was relatively unchanged through 1960. The relatively higher number for black women appears to be almost entirely from black women getting pregnant a lot more often.
  • Current twin births are more than triple those rates of a mere half-century ago.  But the “twin gap” has shrunk, with non-Hispanic whites at around 36 per thousand births and non-Hispanic blacks around 39 per thousand births.  This kind of puts a pin in the notion that it’s substantially genetic in black women.  Maybe, but the rapid changes and closing of the gap suggest environmental factors are the major driver.
  • As recently as 1985, the total twin rate for all races was around 20 per thousand births.
  • Twin births among (white, non-Hispanic) college moms are typically above the national average of around 3%.  They are more like 4-5% in many states, with a lot of it happening in regions where I found third children to be born above the national baseline for third births.
  • Twin births these days are more likely to be second births than first.  I don’t know if that would be the case pre-birth control and pre-ART, it’s hard to find birth order data because live twins were so much rarer until quite recently.



A brief note about Hispanic and Asian married household data

I haven’t been breaking out the Hispanic and Asian data because the oldest consistent data is from the 1980s and most of the data directly comparable to white and black households is from the 1990s on.  It’s also harder to break out because Hispanic and Asian are just broad government terms for a huge array of ethnic groups and a lot of what people mean when they say “Hispanic” or “Asian” only refers to a handful of ethnic groups.

But for the purposes of looking at current married households, I will probably go ahead and add in the Asian and Hispanic data in the next few months when we’re settled down somewhere shiny and chrome, as Asians are almost entirely “college moms” in the most recent 10 years or so of birth data (~85% rate).  Asians are also the group that are most likely to engage in the “one prized, intensively parented child fairly late in life” mothering approach.  They are more likely to do this than the usual bogeyman of college educated white women.

Hispanics, conversely are in a very real sense the direct replacement for the non-college white working class births. They really have filled in the slot formerly occupied by Catholic white ethnic groups in terms of cohesive family structure without a lot of education.

College education and birth numbers, 2007-2015

The CDC has a birth database,, and it is pretty complete.  It’s where the numbers come from.

What I was talking about here  is a little more obvious once the percentages are there.  This is just for black and white non-Hispanic women, the groups you can go back to 1960 or earlier on.

Black women: 53% of births to women with high school completed or less, 47% of births to women with some college education, including completing bachelor’s and advanced degrees.  Nearly 4 million births for that timeframe.

White women: 32% of births to women with high school completed or less, 68% to women with college education.    Nearly 15 million births for them.

These numbers represent all births for this timeframe, first kid, second, fifth, whatever.

Now we look at the impact of education level on marital status for black women:


Race Education Level Percent Married at Birth Percent Unmarried at Birth
Black 8th grade or less 38.49% 61.51%
9-12 grade 9.63% 90.37%
Finished High School 18.30% 81.70%
Some college 27.68% 72.32%
AA degree 44.23% 55.77%
BA/BS 62.28% 37.72%
MA 76.47% 23.53%
PhD or Professional Degree (MD, JD, etc.) 86.00% 14.00%

Though not ideal, the impact of more education is evident, women with even a little college education represent a substantially lower number of out of wedlock births.

Here’s the impact for white women:

Race Education Level Percent Married at Birth Percent Unmarried at Birth
White 8th grade or less 67.41% 32.59%
9-12 grade 30.05% 69.95%
Finished High School 50.39% 49.61%
Some college 63.35% 36.65%
AA degree 79.10% 20.90%
BA/BS 92.69% 7.31%
MA 95.74% 4.26%
PhD or Professional Degree (MD, JD, etc.) 96.06% 3.94%

Amish births distort their 8th grade numbers in favor of marriage, but given the radically different structure of Amish society,  one could argue that this is a more education= more marriage situation too.  It is worth noting that the out of wedlock numbers for white women with BAs or more have remained in the single digits for decades now, despite the group itself being much larger a chunk of the mothers.

Having looked at basic out of wedlock differences by education we come to the question the natalist of any sort is most interested in: what percentage of BIRTHS do the higher-educated moms represent?

Let’s look at the numbers for black women first:

Race Education Level Percent of total married births Percent of total unmarried births
Black 8th grade or less 2.35% 1.48%
9-12 grade 6.04% 22.28%
Finished High School 21.68% 37.99%
Some college 26.26% 26.94%
AA degree 10.04% 4.97%
BA/BS 20.67% 4.92%
MA 10.38% 1.25%
PhD or Professional Degree (MD, JD, etc.) 2.57% 0.16%

And the kicker, percentage of total births:

Race Education Level Percent of all births
Black 8th grade or less 1.72%
9-12 grade 17.70%
Finished High School 33.39%
Some college 26.75%
AA degree 6.40%
BA/BS 9.36%
MA 3.83%
PhD or Professional Degree (MD, JD, etc.) 0.84%

As you can see, the ground gets pretty thin for black women with more education, but they still represent about 20% of total births at the AA+ level, and at that level a comfortable majority of births are in wedlock.  This means most of the 30% or so of black births born in wedlock these days are heavily drawn from that 20% group, despite their smaller separate percentages.  It also means that even including the “some college” group’s high OOW rate, black women have a majority of births in wedlock being born to college educated mothers.

But here’s something interesting with the data for white women:

Race Education Level Percent of total married births Percent of total unmarried births
White 8th grade or less 1.33% 1.54%
9-12 grade 3.41% 18.99%
Finished High School 16.11% 37.99%
Some college 19.53% 27.07%
AA degree 10.42% 6.60%
BA/BS 31.53% 5.96%
MA 13.94% 1.49%
PhD or Professional Degree (MD, JD, etc.) 3.74% 0.37%

If you look at unmarried birth percentages, you see that they are nearly identical in distribution to the black percentages.  They are in fact identical at the “Finished High School” level, with that being the largest chunk of unwed mothers for black women and white women.  What we also see is that for white women, there are MORE college educated mothers having OOW births as a percentage, while they have a smaller group of births in the “Grade 9-12 only” category.

That was surprising.

Here’s the total birth percentages for white women by education level:

Race Education Level Percent of all births
White 8th grade or less 1.39%
9-12 grade 8.00%
Finished High School 22.55%
Some college 21.75%
AA degree 9.30%
BA/BS 24.00%
MA 10.28%
PhD or Professional Degree (MD, JD, etc.) 2.75%


Just like with black women, you get a shrinking of percent from some college to AA and then a strong bump for the BA, but it’s much more significant here.  So even if you don’t care about test scores and all that jazz, the basic cognitive sort is blindingly obvious in both black and white women.  Black women who marry before kids are heavily college attending, and white women in general, but ESPECIALLY those who marry are heavily college attending.

Anyway this post is just putting the numbers up.  These births, as noted in the title, are recent and span nearly a decade and are all births, not just first births.  So these children are almost entirely under 10 years old and this represents some completed families and siblings.  This has interesting implications for the future.

Just how dysgenic is the college gap between men and women?

Vox Day feels that it is quite dysgenic, but I think that we kind of see the Grain of Truth thing going on.

The reality is that 70% of white, non-Hispanic (WNH) births each year for the last decade or so are to college educated women.  And still more reality is that a majority of WNH births have been to college educated mothers since sometime in the 80s, when they crossed 50%.  So for about 30 years now, a majority of white babies are being born to educated white mothers.  And by 1960, the percentage was already over 20%.

Now this is a different issue than raw baby count, but even there, white women had about 2 million babies (after minusing 50k or so Hispanic births, this was before they were a separate category) in 1970 (when college educated mothers were around 25% or so of the total) and in 2015, the most current year available, they also had 2 million babies.

People are having fewer children as a population proportion, that is true, sort of.  But the raw count of kids has been very stable for decades, with its structure changing.  The right wing having a big conversation about what it means that most white kids are born to college-moms would be more useful than asserting that such motherhood is definitely dysgenic.  Which is itself an open question.  Intelligence flows from mom, so is having bright women make up more of the moms (particularly the married moms) dysgenic?  Yeah, yeah “watered down curriculum”, but that means arguing that the ones who can’t complete coursework in even a watered down form are somehow smarter.  Which would be a hard sell.

Even among black women, a higher fraction of mothers who get married before the babies come are college educated.  That is, college educated black mothers are often married before the babies come and non-college black mothers are at scary 90% or so out of wedlock levels.  A majority of black mothers with a BA or greater are married before the kids come.

So we have a larger population with a static baby count and thus a lower birth rate, but the women left who are bothering to have babies, plural are majority college-attending and married.  And they have more higher-order births, they have supermajorities of the 3+ births.

One could make an interesting argument that it was mainly the vanguard of college educated women’s daughters who successfully reproduced.  And that also has pretty far reaching implications.