Looking after kids: it’s lovely but is it work?

Last week, I sent this tweet:

My wife had gone on a well-earned break for the day with a friend, leaving me in sole charge of our two-year old son and five-month old daughter.

We spent the morning around the house, slowly getting dressed, fed, washed and dressed again (we have a five-month old, remember). Finally, blessed with some gorgeous weather, we made it to the local park in the afternoon, before back for tea, bath and bed. Phew!

My point, squeezed into a snippy 140 characters, was in reaction to those who can be heard saying something like: “I put earplugs in/don’t do the night feeds/need lie-ins at the weekend (*recycle as appropriate) because I’m the one who has to go to work.”

I’ve certainly heard it. In my experience, always from men, many of whom I’m fond of and respect. I assume that when it is said, it’s usually from men, given the societal bias for women to take the extended parental leave, though I’m relying mostly on anecdote and supposition.

But, as I was changing the fourth nappy (diaper, my American friends) of the day with a two-year old playing ‘horsey’ on my back, I thought: “this feels on awful lot like work”. And at my office, I can make regular cups of tea, zone out for five minutes to check the news/Twitter and (usually) go the toilet when I want. I would like to see the bladder infection rates amongst parents, because I find myself ‘holding it in’ an awful lot.

From Men’s Health News

Don’t get me wrong, I had a lovely day and adore spending time with my kids. But it is hard graft.

Which is why this attitude really grates. My wife, who is currently on her second period of maternity leave, looks after the kids for the five working days, with our two-year old being at nursery school (preschool, my American friends) a couple of mornings the only partial respite. I did it for one day and felt the pinch.

But as Ian Curtis sang, routine bites hard. Day after day, going through those endless cycles of nappies, changes of clothes, feeding, shushing to sleep, is draining. And when you’re drained, doing it all over again sets up a tiring negative feedback loop.

This becomes even more acute when one considers that stress and lack of support can increase the risk of post-natal depression. Even without leading to such extreme consequences, it is beneficial for a child’s development for the parents to be less stressed. In fact, one study showed that minor daily hassles, which all mothers experienced regardless of background or family set-up, were related to more child behaviour problems, less satisfied parenting and poorer functional family status. The study also emphasised maternal emotional support, either from friends, communities or partners, as an important buffer from these adverse effects and to maintain mothers’ psychological well-being. I can’t even begin to imagine what it’s like to be a single parent, but find my anger rising as society moves to remove support for this group.

Again, I should say, we both get so much joy from looking after them and wouldn’t change them for the world. But it IS hard graft, and is why my wife’s break was more than fully earned.

Obviously, everyone’s situation is different. Many, many partners who ‘go to work’ are committed to helping a stay-at-home partner in the evenings and at weekends. Many people’s work is also incredibly demanding and stressful (more than mine), and this post is not a prescription of what ‘working’ parents ought to do, as it will depend hugely on circumstances.

But if you find yourself justifying an act with, “well I’m the one that works”, then you may want to have a second think.

My feedback for First Great Western trains

Excuse me for deviating from talking about science for a minute, but I need to vent.

I tried to make a complaint to the train company, First Great Western, about the lack of baby changing facilities on their trains. Apparently, my feedback “contains content that may present a security risk” and I was told to “enter more appropriate information” to allow me to submit.

I have absolutely no idea what content was inappropriate and, after 3-4 attempts, had no desire to go through a further lengthy trial-and-error process to push through a simple letter. So I have posted it below. (If anyone can point out the security-threatening content then please do!)

I hope someone from FGW is able to respond:

I took the 0859 to Bath from Brighton (3+ hr journey) on 17th May, with my wife and
2 children (both under 2). I was shocked when I went to change my
10-week old daughter’s nappy, only to be told that there were no baby
changing facilities on board.

It was odd that there were symbols on the toilet doors indicating baby
changing facilities but no such facilities inside. The conductor told
me that FGW had taken them out. I find this utterly incredible.

I had to change my daughter on the dirty floor at the end of a
carriage. The conductor was extremely helpful in the circumstances and
made sure no-one came passed (and gave us £5 for refreshments), but it
was pretty disgraceful I had to do it at all.

It is very family unfriendly and unhygienic, and the decision to take them
OUT seems even more unbelievable. I would love to know the rationale
for this decision.

Matt

I guess I can just be thankful my 22-month old son didn’t have a dirty nappy, then they might have had a few more complaints.

P.S. I did tweet @FGW and had this unenlightening exchange:

[View the story “Baby changing facilities on FGW trains” on Storify]

How to engage a baby

When you share a laugh with your baby, it can be one the warmest feelings as a parent. But is this a genuine mutual exchange, and how does it come about?

This is a video of what is now a classic experiment in developmental psychology. It shows a mother happily engaging face-to-face with an equally happy baby. The mother then ceases all facial engagement – the “still face” – to which the baby reacts by trying, with all its might, to reestablish the happy interactions. It’s quite a marked and powerful effect:

A historical review of the experiment quotes the researchers who first documented the effect:

“the infant first “orients toward the mother” and “greets her expectantly.” But then, when the mother “fails to respond appropriately,” the infant …

… rapidly sobers and grows wary. He makes repeated attempts to get the interaction into its usual reciprocal pattern. When these attempts fail, the infant withdraws [and] orients his face and body away from his mother with a withdrawn, hopeless facial expression.”

The experiment, in this form, was first presented at a scientific conference in 1975, but it wasn’t the first to document what happened when infants are exposed to varying social interactions. It was, however, the first to use “then-novel videotape technology” on the conference hall’s big screen. Adamson and Frick, in their historical review, suggest that the  immediate and dramatic illustration of the phenomenon contributed to the broad interest this experiment gained. An early lesson in the power of ‘modern’ technology for effective science communication and to maximise research impact.

This may all seem a little obvious to some parents. You may feel that you don’t need a psychologist with a video camera to tell you that a baby is happiest when you are engaging them face-to-face. But there are a number of reasons why the methodical description of this effect has had profound and lasting influence.  

What this experiment first showed, by deliberately manipulating the parent’s engagement, was that the baby is an active player in this exchange. The infant’s social behaviours can influence the parent’s level of engagement, just as the parent can influence the baby, and it can subtly alter these depending on the context. It’s not simply the parent reacting to the baby’s randomly generated cues. It has even been detected in babies as young as a few weeks old.

As Jason Goldman at The Thoughtful Animal says:

“The still face experiment demonstrated that very young infants already have several basic building blocks of social cognition in place. It suggested that they have some sense of the relationship between facial expression and emotion, that they have some primitive social understanding, and that they are able to regulate their own affect and attention to some extent. The infants’ attempts to re-engage with their caregivers also suggest that they are able to plan and execute simple goal-directed behaviors.”

But one reason why this experiment has been so important and enduring is that it provided a standard and reproducible way of measuring children’s social emotional development.

By using the same set-up time-and-time again, it has shown how a child’s social and emotional development becomes richer as they grow older. The response becomes increasingly complex with age, and can include deftly timed facial cues, dampened smiles, sideways glances at their parent and yawns. Adamson and Frick cite a lovely example for the original set of experiments in which a five-month old boy, upon encountering a still face, stopped being wary and…

“…looked at the mother and laughed briefly. After this brief tense laugh, he paused, looked at her soberly, and then laughed again, loud and long, throwing his head back as he did so. At this point, the mother became unable to maintain an unresponsive still face.”

An experience I’m sure many a parent can relate to when – armed with a stern face – they try earnestly to tell off their child, only to be met with a cheeky grin or giggle!

The experiment has also allowed researchers to deconstruct these parent-baby social interactions into visual, auditory and tactile components. Vision and hearing, it seems, is especially important as children get older, but touch can be enough to, at least partially, lessen an infant’s anxiety when confronted with a still face.

Nevertheless, a still face is usually enough to produce the basic negative reaction in a child, even if it’s in response to their mother, father, a stranger or someone on television. Children make a distinction, however, for inanimate objects, even if they appear quite human-like, demonstrating their ability to form genuine social relationships.

This experimental set-up has also revealed possible negative consequences of a parent’s still face. According to Adamson and Frick, children actually show a more dramatic reaction to a still face than to a brief period of separation or to situations in which the parent interrupts interactions to talk to a researcher. Babies assimilate and react to a negative social cue, rather than simply becoming distressed at the lack of stimulation.

The “still face” experiment has shown its use in further understanding various developmental disorders, such as Down’s syndrome, deafness and autism, as well the effects of environmental conditions like infants exposed to cocaine prenatally or to depressed mothers.

The still face experiment has been used to ask questions about how early social and emotional engagement may affect later behaviour. The strength of an infant’s still face effect has been linked to their mother’s normal sensitivity and interactive style, and it may predict the degree of later infant attachment, depression or anxiety, and even behavioural problems.

Clearly, parents who may have a lower level of engagement, such as those experiencing postpartum depression, should not be guilt-tripped, especially as this could have an exacerbating effect. But the still face experiment has shown that simple procedures can help in these situations – depressed mothers who are encouraged to provide more touch stimulation are often able to offset the lack of visual or auditory engagement to bring about more positive social interations.

As Ed Tronick – one of the original researchers of the “still face” experiment – says on his website:

“An infant’s exposure to “good, bad, and ugly” interactions with the mother, as repeatedly communicated by her facial expressions or lack of expression (i.e., a still-face) has long-term consequences for the infant’s confidence and curiosity, or social emotional development, with which to experience and engage the world.

Though let’s not forget the role of fathers, or other partners, either.

[Thanks to mum-in-law Jenny (once again) for the video and @matthewcobb for the Adamson and Frick article]

Hooray for vaccines

I saw this simple but illuminating infographic on the Forbes website, in an article by Matthew Herper. It was created by graphic designer Leon Farrant and shows the profound impact effective vaccines have had on a nation’s health. As Herper explains:

Below is a look at the past morbidity (how many people became sick) of what were once very common infectious diseases, and the current morbidity in the U.S. There’s no smallpox and no polio, almost no measles, dramatically less chickenpox (also known as varicella) and H. influenza (that’s not flu, but a bacteria that can cause deadly meningitis.

20130320-215714.jpg

Vaccine Infographic | Leon Farrant

I saw this not long after watching the British charity fundraiser Comic Relief, which supports aid and development projects in many African countries (amongst other things). One of the recurring themes in the telethon was the urgent need for vaccines in certain parts of Africa, and the devastation that preventable diseases are having on children’s lives.

Worthy, heart-wrenching and persuasive stuff.

But I couldn’t help feel even more frustration than I normally do that, despite having immediate access, many parents in developed countries like the UK and US still choose not to vaccinate their kids. As we have seen with a rise in whooping cough cases and measles in recent years, and as the infographic elegantly shows, a failure to properly protect the population can lead to serious health consequences.

—-

[And for a thorough rebuttal of antivaxers’ scaremongering, read David Gorksi at Science-Based Medicine]

*Infographic is licensed under Creative Commons CC BY-NC-ND 3.0.

Does the sun make you sneeze?

This is a video I took of our little one, sitting in a chair watching telly. As I walk over to him the sunlight streaming in through window catches him full in the face, and a couple of seconds later he sneezes.

This happens to him fairly often, usually as we leave the house into the bright sunlight. I noticed this behaviour straightaway, as the exact same thing happens to me when I move from dark to bright light.

It turns out that this doesn’t happen to everyone, as I found out when I said casually to friends, “you know how the sun makes you sneeze, well…”, and was met with stony silence.

Then I found out I had a proper disorder. Gosh!

It’s called a photic sneeze reflex, or as some witty scientists labelled itAutosomal dominant Compelling Helio-Ophthalmic Outburst – ACHOO syndrome for short. It is estimated that 17-35% of the population have it, and it’s far more common in white people than in other ethnicities.

But no one knows why it happens. Despite it apparently being noticed by Aristotle and investigated by philosopher Francis Bacon, little research has been carried out. My search in the biomedical database PubMed turned up only 16 research papers since 1984.

The best guess at the moment is that it’s because the nerve cells that carry information from the eye and those that carry information from the nose run so close together. As the nerves from the eye are stimulated by bright light, usually to constrict the pupil, electrical signals ‘spillover’ and activate the nerves coming from the nose. This causes the brain to confuse a bright light with a nose irritation, and… ACHOO! In fact, the area of the brain responsible for processing visual information is overstimulated in photic sneezers compared with non-sneezers, which may underlie the spillover effect.

We do know that it appears to run in families – as it has seemingly done in our case – but the genes at the root of it are not known. Initial studies claimed that a child has a 50% chance of inheriting the ‘disorder’ from a photic sneezing parent, but there may be more than one ACHOO gene.

It’s a fairly harmless reaction, though the US air force were sufficiently concerned to fund research into whether this reflex could endanger jet pilots. It could, but was easily overcome with sunglasses.

You may be tempted to speculate as to whether it evolved for a purpose. In all likelihood it didn’t, it is a quirk thrown up by evolution but one that’s not disadvantageous enough to be selected against.

It is irritating, but at least it doesn’t happen during sex.

Should babies watch TV?

This question seems to trouble many parents, and can cause a lot of guilt too.

“Will the TV numb my baby’s brain?”

“Are they destined for a sedentary life?”

“AM I CONDEMNING THEM TO LIFE AS A MINDLESS AUTOMATON?!”

This is why an interview last week with psychologist Annette Karmiloff-Smith on the BBC’s The Life Scientific caught my ear (thanks to a pointer from mum-in-law, Jenny). It’s a fascinating insight into how babies learn to learn, and how their brains develop to understand the world around them. You can listen here: The Life Scientific.

But on TV watching, Prof Karmiloff-Smith, an expert in developmental disorders, argues that if the subject matter of the programme is carefully chosen and scientifically based, then the TV can be better for a child’s learning than even a book.

This was largely in response to advice reissued by the American Academy of Pediatrics (AAP) that babies under two shouldn’t watch any TV or DVDs. There are three main concerns: poorer language skills, a negative effect on sleep, and less time spent taking part in other types of unstructured play that are critical for the proper development of mental capabilities.

This is based on a growing body of scientific research. TV/DVD watching is common: in the US at least, by two years old over 90% of children regularly watch TV, spending an average of 1-1.5 hrs a day in front of the box. Very young babies (under 1.5 years old) cannot, however, really understand TV programmes, and are instead mainly attracted by obvious changes like applause or visual surprises.

Children learn new words or actions better when an adult is teaching it to them live, rather than via a television screen, and the worry is that parents talk to their kids less when the TV is on. And a growing number of studies suggest that children who spend longer watching TV/DVDs have delayed language development, at least in the short-term, and may also develop a worse attention span.

A child’s play may also be hindered by the distraction of a TV that’s on in the background, so the AAP advise to turn it off altogether. Many parents also use TV/DVDs as a sleep aid, but there is evidence that bedtime viewing may lead to more disturbed and shorter sleep.

Karmiloff-Smith, on the other hand, argues that we live in a media saturated world and it’s unrealistic to expect parents to shut down all media use. This view has support from some of the evidence cited in AAP report itself. Despite the original recommendation in 1999 that parents should be discouraged from letting their babies watch TV/DVDs, over 90% of them in the US currently do so by the time their child is two years old. What’s more, the average age that TV is introduced is 9 months, so the advice is clearly not striking a loud enough chord.

From my experience, I can certainly appreciate this. The AAP report says that many parents use the TV so that they can have a shower or cook dinner. Absolutely! Even these seemingly mundane activities can feel like an exercise in military-like efficiency when you’re looking after a child. A 10-minute respite when they’re quiet and content gazing at a TV or prodding an iPad can be just too tempting.

It’s also interesting to consider that throughout history many new technologies have been treated with caution. Dr Vaughan Bell, a psychologist based at King’s College London, has highlighted how the printing press, popularisation of the radio, and now the Internet have been damned for ruining kids’ brains.

Karmiloff-Smith goes on to say that, rather than banning TV for babies, TV programmes just need to be made better and based on science developments. For instance, the visual system is attracted by movement, but most kids’ TV programmes have their focus on the centre of screen. Instead, objects and features that come in from the sides, move across screen and encourage the child to interact promotes the active participation that’s good for mental development. For very young babies, moving image media may even have advantages over books, which are static and whose main attraction is the rustling of the pages.

The caveat in this is that Karmiloff-Smith reveals herself to be a scientific consultant to a DVD company that is designing such programmes. This could cause suspicion of a financial conflict of interest. But her honesty and gusto make me suspect that she became a consultant so that she could promote these ideas, rather than the other way around.

She finished the interview by emphasising that parents still need to interact with their children and the TV shouldn’t be used as a babysitter. But we should think more carefully about which types of media can stimulate the visual and auditory systems, so as to help train the attention and memory systems early.

I’ve written before about the various kinds of programmes and the various contexts in which kids can watch TV, which may have different effects on child development. And some of the evidence cited in the AAP report highlights these complexities. The effects on children’s attention, for instance, seem to depend on the programme content and style, with problems seen not when the content is deemed educational but only when it’s geared towards entertainment. And when a parent watches a programme with an infant and talks them through it, the child tends to become more attentive and responsive. The AAP report also points to evidence that watching Sesame Street can have a negative effect on expressive language in children under two. But the same study showed that watching other programmes, such as the North American-based shows Dora the Explorer, Blue’s Clues, Arthur, Clifford, or Dragon Tales, was associated with greater vocabularies and higher expressive language scores. So it appears that not all ‘screen time’ is equal.

The AAP report seems to fall into the trap of treating all TV and DVD viewing as the same:

For the purposes of this policy statement, the term “media” refers to television programs, prerecorded videos, Web-based programming, and DVDs viewed on either traditional or new screen technologies.

Another major limitation of the AAP report is that all of the cited studies are, by necessity, observational. These investigations are good at highlighting whether two factors are associated with each other, but they cannot tell you whether one causes the other. As the report itself asks, are children with poor language skills simply placed in front of the TV more? Are children with shorter attention spans more attracted to screens? Are parents who are less attentive on the whole, more prone to resort to screen time? If so, then turning the TV off would not necessarily lead to more parent-child interactions.

And some results are just contradictory. One study in the US showed that when the mother’s educational status and household income were taken out of the equation, the association between TV viewing and poor language development disappeared. This appears to have been glossed over by the AAP.

So how do I answer my original question?

The AAP are right to caution against a lot of TV for under twos (over four hours a day, say), as this is when the damaging effects are really apparent. But Karmiloff-Smith is also right to say it’s unrealistic to expect no TV at all, and that the right programme in the right environment is fine and potentially beneficial.

And I’ll leave you with this quote in Time from Dr Dimitri Christakis, a paediatrician at Seattle Children’s Hospital:

Ask yourself why you’re having your baby watch TV. If you absolutely need a break to take a shower or make dinner, then the risks are quite low. But if you are doing it because you think it’s actually good for your child’s brain, then you need to rethink that, because there is no evidence of benefit and certainly a risk of harm at high viewing levels.

Parenting science: 12 top stories of 2012

It’s that time of year when we’re flooded with ‘best of’ lists, so allow me to jump on the bandwagon. 2012 has been a great year for science – the discovery of the Higgs Boson, the landing of Curiosity rover on Mars, and the ‘encyclopaedia of DNA’ that has given us the deepest insights into the human genome.

Here, I’ve picked out some of the stories that might interest parents, covering areas such as child learning and development, reproductive technologies, embryology, genetics, and even a bit of public policy thrown in. I’m sure I’ve missed some interesting ones too, so please add yours in the comments!

Mouse eggs created from stem cells for the first time (New Scientist)

Once a fully functional body cell develops from a ‘parent’ stem cell, it’s thought there is no going back to the previous state. A team of scientists in Japan, however, used a cocktail of signalling molecules to reprogram skin cells to become immature egg cells in mice (they had already done this to create sperm cells). What’s more, these cells could be fertilised and, in some cases, led to healthy mouse pups. This was a stunning feat of biological engineering that will help in the study of mammalian development and also hold promise in treatment of infertility. In a related story, controversy over whether biology textbooks need to be re-written took a turn when more convincing evidence was published that the number of eggs in a female isn’t fixed for her lifetime but can instead by replenished from a stem cell stock.

‘Chimera’ monkeys created in lab by combining several embryos into one (The Guardian)

The headline is pretty self-explanatory and the article itself is a fascinating read, so I won’t re-invent Ian Sample’s superbly crafted wheel. So if you want to know more about the controversial technique of creating normal, healthy monkeys with cells from more than one embryo and why it might benefit stem cell therapies, go read it! This may not be as bizarre and ‘unnatural’ as it first sounds, though, as we may all be walking chimeras and carry cells from siblings, aunts and uncles.

Genome Sequencing for Foetuses (Wired Science)

Being able to test foetuses for genetic faults that increase the risk of a serious disease, such as Down’s syndrome and blood or nervous system disorders, is hugely important. This is currently done mostly by invasive techniques such as taking samples of the placental tissue or amniotic fluid. This study, however, showed that it’s possible to work out the foetus’ genetic make-up by piecing together tiny fragments of DNA floating around in the mother’s blood. The ease of such a test would, of course, raise ethical issues about what is appropriate to screen for and what counselling parents would need, as well as requiring a firm and clear communication of risk.

DNA-swap technology almost ready for fertility clinic (Nature News)

Mitochondria are little energy powerhouses within most of our cells and they contain a small amount of their own DNA that is inherited wholly from the mother. A range of devastating diseases, that can affect the brain, liver, muscle and many other organs, are caused by defects in this mitochondrial DNA. A group of US researchers showed it was able to swap the mitochondria in a mother’s egg with one from a healthy donor to produce a normal looking embryo free from the mitochondrial genetic faults (restrictions on this technology would not allow a live birth). You can read about how the scientists actually did this in David Cyranoski’s article. And I would add that, contrary to some scare stories, these would not be ‘3 parent babies’ – mitochondrial DNA contains only 37 genes (involved in protein synthesis and biochemical reactions that make up respiration) compared with the many thousands of genes coded for by the DNA in the nuclei of our cells.

Babies are born dirty, with a gutful of bacteria (New Scientist)

Earlier this year I blogged about the “The microworld that lives inside you” and how the microorganisms that outnumber our own cells 10:1 are first transmitted from mum as a baby is born. A study by Spanish scientists, suggested that this isn’t the whole story. By studying the “meconium” – the baby’s first poo that is made up of materials ingested during the time in the womb – they detected two types of well developed bacteria. We don’t know for sure, but these were probably passed from the mother through the placenta. Our so-called “microbiome” is really important, because it influences our digestion, immune system, risk of disease, and maybe even our personalities.

Childhood stimulation key to brain development, study finds (The Guardian)

A US study provided more evidence that a sensitive period of learning and development exists early in childhood. They surveyed children from when they were four years old, recording details such as the number of books and the types of toys they had, to measure the amount of mental stimulation to which they were exposed. They also scanned the brains of the same children when they were between 17 and 19. As Alok Jha explains: “…the more mental stimulation a child gets around the age of four, the more developed the parts of their brains dedicated to language and cognition will be in the decades ahead.” Of course, this was an observational study and so limits the strength of the conclusions about whether the types of toys really caused brain developments, but the way the researchers tracked the same children over many years and the factors they took into account (parental nurturance had little effect, for example), was particularly impressive. Another cautionary note: the results were presented at a scientific conference and, as far as I know, have not appeared in a scientific journal, which means it won’t have yet been properly quality assessed by experts.

Golden ratio discovered in uterus (The Guardian)

At the risk of straying into mysticism, this was a nevertheless alluring report of a Belgian gynaecologist’s claim that the uterus represents an aesthetically pleasing “golden ratio”. This ratio is derived from something called the “Fibonacci sequence”, which is a sequence of numbers starting 0,1,… where every subsequent number is the sum of the previous two (so: 0, 1, 1, 2 , 3, 5, 8, 13, 21,…). The ratio between pairs of number in the sequence (divide one by the other) ends up being 1.618, which is the “golden ratio”. As Alex Bellos explains, its devotees believe it expresses aesthetic perfection and is found wherever there is beauty. According to Dr Verguts, when women are between the ages of 16 and 20 and at their most fertile, the ratio of uterine length to width is 1.6, spookily close to the “golden ratio”.

What happens to women denied abortions? This is the first scientific study to find out (io9)

Another set of results presented at a scientific conference, rather than in a scientific journal, but that is worth noting nonetheless. Annalee Newitz cites a Facebook post written by the lead researchers of a study that followed up women who had sought abortions at different abortion clinics in the US: “We have found that there are no mental health consequences of abortion compared to carrying an unwanted pregnancy to term. There are other interesting findings: even later abortion is safer than childbirth and women who carried an unwanted pregnancy to term are three times more likely than women who receive an abortion to be below the poverty level two years later.” Newitz further emphasises the preliminary results: “When a woman is denied the abortion she wants, she is statistically more likely to wind up unemployed, on public assistance, and below the poverty line.” If these findings turn out to be valid when further quality checks are carried out, they could help shape the debate on abortion policies and the state support a women seeking an abortion receives.

Boys and girls may be entering puberty younger (New York Times and The Guardian)

A study on the timing of puberty in boys by the American Academy of Pediatrics complements an earlier study on girls, which both hinted that puberty is, on average, starting gradually earlier in both sexes. Current estimates, at least for US children, are that the average age of puberty onset is around 9 years in black boys and girls and around 10 years in white boys and girls (although full sexual maturity may happen later than this). No one, as yet, knows why, but speculations include diet, changes in physical activity, improvements in healthcare, and chemicals present in the environment that affect our hormones.

Fathers bequeath more mutations as they age (Nature News)

A Swedish study concluded that a father passes on more genetic mistakes to their children than do mothers, and the older the man, the more mutations he is likely to pass on. This is most probably explained by the fact that sperm are generated from dividing ‘precursor’ cells throughout a man’s life and this cell division becomes less precise with age. Most inherited mutations won’t lead to any problems for the child, but the occasional one may increase the risk of a genetic disease like autism or schizophrenia. Taken together with rising average age of fatherhood, does this help explain, at least in some part, why autism rates are rising? (It could, but awareness and diagnostic changes are also likely to be at play). It’s not definitive and it shouldn’t scare older would-be fathers, but it may help in better informed decision-making.

An HPV Vaccine Myth Debunked (New York Times)

One of the arguments opposing vaccinating children against the Human Papilloma Virus (HPV), which can cause warts and cancer, is that in the minds of the young girls it frees them up to be sexually more promiscuous. Studying long-term medical data from girls in Atlanta, USA, however, showed no difference between vaccinated and non-vaccinated girls in pregnancies, sexually transmitted diseases, testing for sexually transmitted diseases, or contraceptive counselling. The article finishes by saying: “As one expert said, parents should think of the vaccine as they would a bicycle helmet; it is protection, not an invitation to risky behavior.”

Hungry mothers give birth to more daughters (Nature News)

Another eye-catching story was the report that during the Chinese Great Leap Forward famine, the proportion of boys being born dropped (from 109 boys for every 100 girls to 104 boys for every 100 girls). This sets up the tantalising possibility that sex ratios are adjusted in response to environmental conditions such as nourishment, a situation already known in deer where undernourished males tend to have fewer offspring than undernourished females (although in humans other factors like psychological and physical stress could be at play).

A final story that caught my eye was the latest results from the Avon Longitudinal Study of Parents and Children (ALSPAC), also known as the Children of the 90s, which probably warrants a blog post in itself. Nature News covered it and The Guardian’s sublime Science Weekly podcast featured it too (after 26:10). My favourite bit was how they collected the children’s milk teeth: “We had to negotiate for those. They are worth money to children, after all. In the end, we only got the milk teeth when we presented each boy and girl with an official Alspac form, signed by the tooth fairy.”

How sweet!