2 observations without having read the details of either study:

1.If the mother's IQ explains the decision to breast-feed it must have been difficult to find the sample of sibling pairs in which one was breast-fed and the other not.

2. Media coverage of first study claiming to find a gene-environment interaction fits well into the general pattern:

-If the findings are "politically sensitive": Emphasize that nothing is conclusive yet; even stress doubts on the general concept of IQ
-If not: Give the study unreserved coverage.
http://www.economist.com/ science...ory_id=10097684

To what extent did the Scottish paper investigate the "dose effect" IE the longer a child is breastfed the higher their IQ. Does higher maternal IQ also correlate well with the amount of time spent breastfeeding?

1.If the mother's IQ explains the decision to breast-feed it must have been difficult to find the sample of sibling pairs in which one was breast-fed and the other not.

I don't see why. Plenty of women may breastfeed, say, their first child out of good intentions, but find it bothersome and revert to formula for their second or third. Changes in circumstances could also affect their decision.

My mom breastfed my oldest sister, then decided it was too much of a bother and bottle fed her next three kids. Now she wonders why it took me five and one half years to graduate college. Stupid b*tch. (Kidding! I love my mom.)

Not hard at all...many mothers breastfeed some but not all of their children. For example, my first child was premature and had a great deal of trouble breastfeeding; she was bottle-fed from 8 weeks on. My second and third were full term and were breastfed. Other things like illness or a need to return to work can also influence whether children in the same family are breastfed or not.

My oldest child still tested at an IQ of 127, despite being bottle-fed. Which led me to conjecture that breastfeeding is probably not the most important determinant of a person's IQ. Otherwise, sub-Sarahan Africa (where babies are commonly breastfed for three or four years) would have stratospheric IQ scores.

However, I would (based upon my own completely unscientific observation) agree that the mother's IQ does have a lot to do with whether she breastfeeds or not.

Things like educating yourself about breastfeeding, mastering the technique (it's harder than you would expect), the time commitment involved (can't just leave baby with a sitter for the entire night while you go out clubbing), and the logistics problems presented by working and breastfeeding definitely have an impact on the kinds of people who breastfeed.

For working women, the difference between having a high-level white-collar job with twelve to sixteen weeks of maternity leave and a pink-color job with six weeks or less of leave can make a huge difference, as it often takes at least eight weeks to really get the hang of things, not to mention building up a stockpile of pumped milk to send to daycare.

An educated woman who keeps informed about health and nutrition, understands the concept of delayed gratification (the first month of nursing is often EXCRUCIATINGLY painful until you and baby get the hang of it), and who either does not have to work or works somewhere with a flexible schedule and privacy for pumping milk is FAR more likely to breastfeed than a high-school dropout who works as a waitress and likes to go out partying til 4 AM on the weekends (after all, she is only nineteen years old and single). I'm sure you can figure out which of these two hypothetical women likely has a higher IQ.

Well said, Salamander. It's about time they got an informed view, and that's as good as I've seen. Too many well intentioned women are made to feel guilty or inferior about this by the gung ho crowd who insist that any mother who really wants to breast feed her child can do so, no problem. It often isn't that simple,

My wife did her level best, but she had health problems after 2 weeks, and that was the end of it.

Now my daughter is irritated because her IQ is only 146 and she thinks it could have been 153. I told her she scares me enough at 146.

a comment from a neonatologist:

1. If PUFA are that important ( and the aap says that the jury is still out- but what do they know) there are plenty of PUFA in formulas now.

talk of politically incorredct message from someone in my profession

The media coverage of a potential genetic link between breastfeeding and IQ is good for scientists studying the genetics of intelligence. Researching gene-environment interactions is wise. Most people would love to find an environmental fix for the black-white IQ gap. If genetic research into IQ differences is seen to further that agenda it will gain far more support.

I just want the research done. I want to know how genes, cells, and brain structures interact with the environment to produce human thinking.

And there will be many benefits to that knowledge...preventing and healing mental diseases, improved mental performance due to better nutrition, drugs, and training.

Or perhaps breast-feeding your baby increases your IQ. An environmental effect on IQ - bound to find favour somewhere.

Otherwise, sub-Sarahan Africa (where babies are commonly breastfed for three or four years) would have stratospheric IQ scores.

Do you have a cite for this? Sub-Saharan birthrates are pretty high for this to be true.

My ex refused to breastfeed our daughter, as she found it time consuming and tiring. She did agree to pump breast milk, which I stored and fed our daughter - who at 4.5 yo is very bright.

My question, is it breastfeeding per se, or being fed breast milk that matters??

Also, has anyone ever tested a possible link between breast size and a particular effect on breastfed male infants?

Breast milk builds the immune system in the child. This and other physical good things are pretty well established. It also makes sense that some sort of security and bonding would occur--this is, after all, the natural food for mammals. But the IQ angle was never on solid ground. How much nutrition affects intelligence is questionable. Still, a lousy diet might make it hard to take a test--too much sugar is terrible for concentration. A Frenchman I know said it was common knowledge in his country that a lot of kids who were very young during WWII, when there were food shortages, grew up shorter than average. But nobody noticed a lesser intelligence in them on the average.

"Breast milk builds the immune system in the child. This and other physical good things are pretty well established... But the IQ angle was never on solid ground."
Building the immune system to prevent infections with deleterious effects on brain development is a plausible mechanism for an IQ boost.

A bit off topic, but all three reactions to Flynn are now up at Cato Unbound.

Rob, I just looked up the breastfeeding rates for sub-Saharan Africa and they are only 34% for infants ages 0-4 months, according to WHO! I wonder what the heck they are feeding those babies? Formula and clean water can't be easy or cheap to come by there; I suppose they are giving them goats milk or some such thing...

Now, I had always been told that African babies were breastfed for 3 or 4 years -- mostly by members of the La Leche League who were trying to convince me it was perfectly normal to be nursing a preschooler...I guess this just goes to show that we need to seek the truth ourselves and not trust what people with agendas try to tell us.

Thanks Salamander,

I wasn't trying to be a jerk, but I thought rates were lower than what a westerner might expect. I did not imagine rates were that low. That is really sad. Did WHO say why? Is it because of high HIV infection, or is formula a status symbol?

I once read an anecdote from Sarah Blaffer Hrdy(maybe) that the only people who breastfeed for 4 years are San Bushmen and anthropologists.

I'm not really big on social engineering that I don't like, but I'm really starting to think that women should be paid to breastfeed. Or formula makers should have the hell taxed out of them.

And that means SSAs can get a couple points of IQ from equalizing to white American breastfeeding rates.

Environmental IQ gap strikes again!

Again i would like to add - as a neonatologist who deals with these issues day by day- the breatfeeding story is currently undecipherable scientificaly. The genre is full of poorly designed studies, outright myths, opinion masquerading as fact, propoganda, political correctness; occasionally interspersed with some sound studies. without trying to dis anyone many of the comments above fall into the mythology category.

The PC angle works thus, virtually any garbage " research" that says br feeding =good' formula = bad has a better than even chance of getting pubished.

The first paper I ever published as a fresh green trainee who didnt know any better was about the possible active immune functions of leukocytes in breast milk. I am sorry to say- if I could remove my name from the study, I would gladly do so. It was utter unmitigated garbage- I am embarrased by it (needless to say my faculty preceptor whose brainchild this piece of shit research was is currrently a top adminstrator reviewing grant proposals at the NICHD. My co trainee on the study who had no such scruples is now the top doc executive at a childrens hospital, and I opted out of this unethical crap that goes for medical research and am very happy in practice).

to summarize:

1. a lot of breat milk studies - utter crap
2. Formulas undergoing constant eimprovement wrt constituents. No earthly reason why they cannot get pretty durn close to br milk over time.
3. If Polyunsaturated fatty acids (PUFA)are truly the link between br feeding and IQ, then rest assured - the formulas made by Meade johnson have as much/ more PUFA than br milk, nad i am guessing the other companies are going to follow suit as soon as they can.

So unless you are jewish or catholic - stop guilting obsessively about br feeding. reject the religion of the boob

Reject the religion of the boob?

You worship your way, and I'll worship mine.

Finding that the breastfed sibling of a pair is not the smarter one is pretty damning.

Me and Aggers is bum worshippers - we know the significance of a healthy waist-hip ratio.

"not trust what people with agendas try to tell us" - yes, absolutely. PC fuels a lot. Surrounded by bloated CEOs on one side and wannabe world-savers on the other. Objectively seeking to see reality is the only way.

When people come down so strongly on one side or another of the breastfeeding issue (or, indeed, dairy food in general), I wonder if Freud got it right after all. The phobias of the vegan are particularly enlightening even tho I'm an alternative sort of gal myself.
One year is the maximum time Mom should do this. My high school teacher from France hated milk and said her mother had breast fed her for five years. She gave no more details.
We know the ancient Hebrews weaned their kids at 3 years because that's when Moses was returned to Pharoh's daughter after being "wetnursed" by his own mother. Three years was when a boy began to hang out with the men folk.
I can tell you breastfeeding does help the figure get back into shape if the feeding doesn't go on too long, and it is better for the child's immune system, or at least the breast-fed compared to bottle fed children I have known. However, this would depend a lot on the diet of the mother. If she's eating crap she as well bottle feed. There are many variable you have to take into consideration.
But again, breast milk like any food, is probably not responsible in and of itself for IQ.

The new breastfeeding study is more junk science that I debunked at my blog.

Breastfeeding does NOT boost IQ.

Formulas undergoing constant eimprovement wrt constituents. No earthly reason why they cannot get pretty durn close to br milk over time.

And until they become true approximations of breast milk, why should we encourage people to feed their children inferior and possibly deficient versions of the real thing?

The point seems to be that people are strongly motivated to choose things that are immediately convenient for them, but then feel guilty for choosing convenience over quality and need to convince themselves that the option they've chosen is just as worthwhile as the one they rejected.

I wasn't trying to be a jerk, but I thought rates were lower than what a westerner might expect. I did not imagine rates were that low. That is really sad. Did WHO say why? Is it because of high HIV infection, or is formula a status symbol?

Don't worry, no offense taken! It's good that we are looking up actual statistics instead of just relying on hearsay.

The WHO site did not say why rates were so low. But, these are a couple of my hypotheses:

1. Formula is often a status symbol in developing nations, vs. the US where it is starting to develop a lower-class connotation (hence all the Rich and Famous celebrities who claim to be ardent breastfeeders). Here in the US, in the early and mid-20th century, formula was very much a status symbol. Only people too poor to afford it breastfed (you can ask your grandparents if you don't believe me; my own mother was rather horrified that I nursed my babies -- it seemed very Ellis Island to her).

2. Some African cultures believe that a pregnant woman's milk is poisonous. While breastfeeding acts as a natural suppressant of ovulation in many women, it does not in others. So if a woman got pregnant again, she might well wean her baby immediately from health concerns.

3. Along the lines of #2 -- in a culture where the number of children is a status symbol, a woman might wean early to regain her fertility

4. High HIV rates might be skewing the numbers, as breastmilk can transmit the AIDS virus.

Really, I was shocked that the rates are so low over there. If any place is justified in nursing for three or four years, it would be an area in which a) there is not much else to eat, b) minimal sanitation and health care, and c) limited access to birth control. Go figure.

Cool beans.

I did not know #2, it sorta makes sense. The developing fetus is competing with the nursing baby for maternal resources, so breastfeeding while pregnant might be bad for all three.

"High HIV rates might be skewing the numbers, as breastmilk can transmit the AIDS virus."

Yep: Step to decrease AIDS in Botswana backfired fatally

In that report the grieving mother says:

"That was the only boy child I had," said Mavundu. "I loved him very much."

I am surprised that the PC editors let that quote through.

"In that report the grieving mother says:
" 'That was the only boy child I had," said Mavundu. "I loved him very much.'"
I am surprised that the PC editors let that quote through."

How do you figure that Some Random Weirdo? That sentiment, obviously heart felt, is prima facae evidence for son preference.
It's something a PC artist editor would most certainly frame in neon-lights.

How do you figure that Some Random Weirdo? That sentiment, obviously heart felt, is prima facae evidence for son preference.
It's something a PC artist editor would most certainly frame in neon-lights.


Someone with more experience of the world would realize that mothers often love their sons more while fathers often love their daughters more.

It is prima facae evidence that that mother loved her son, but it does not fit the narrative that males oppress females to the extent of preferring male children over female children. In this case it was a female expressing that view.

That is such a sad situation. But not entirely unexpected...as anyone who has formula-fed a baby knows, it's expensive; you have to have access to formula; you need clean water; and you have to be careful to keep the bottles and nipples very clean. It's not such a big deal here in the US to do all that, but I would not want to be living out in a remote Third World area and be dependent on formula.

I'm being facetious Some Random Weirdo, and thinking how psychology works.
It's not a "feminist" thing, this son vs daughter preference. It is a fact for which there were sometimes quite valid enough reasons. But if men loved daughters more all this time, they've sure had a weird way of showing it in most places down through the ages. Mohammed could tell a few tales.
Modern people, especially we in the "west", have the luxury of prefering any sort of entity upon which we wish to lavish fondness: cats, dogs, frothy coffee machines, males, females, neither, etc.. Now all kids, sons and daughters alike, are really liabilities, not assets, so if you have them it's because you want them. In theory. We don't need sons to light our funeral pyres or say prayers for our KA or carry on our lineage. We don't need daughters to light the lamp or carry the wash down to the river. Instead, both sexes require their parents spend a million or so dollars on them, to Give Them a Good Start. Anway things change. I understand that Japanese today do prefer daughters. They think life will be easier for them than for sons. The salary man life is just too much of a grind.