but first of all I'm going to ask you a couple of questions.

How many people here have children?

And how many of you are confident

that you know how to bring up your children

in exactly the right way?

(Laughter)

OK, I don't see too many hands going up on that second one,

and that's my confession, too.

I've got three boys;

they're three, nine and twelve.

And like you, and like most parents,

the honest truth is I have pretty much no idea what I'm doing.

I want them to be happy and healthy in their lives,

but I don't really know what I'm supposed to do

to make sure they are happy and healthy.

There's so many books offering all kinds of conflicting advice,

it can be really overwhelming.

So I've spent most of their lives just making it up as I go along.

However, something changed me a few years ago,

when I came across a little secret that we have in Britain.

It's helped me become more confident about how I bring up my own children,

and it's revealed a lot about how we as a society can help all children.

I want to share that secret with you today.

For the last 70 years,

scientists in Britain have been following thousands of thousands of children through their lives

as part of an incredible scientific study.

There's nothing quite like it anywhere else in the world.

Collecting information on thousands of children

is a really powerful thing to do,

because it means we can compare the ones who say,

do well at school or end up healthy or happy or wealthy as adults,

and the ones who struggle much more,

and then we can sift through all the information we've collected

and try to work out why their lives turned out different.

This British study -- it's actually a kind of crazy story.

So it all starts back in 1946,

just a few months after the end of the war,

when scientists wanted to know

what it was like for a woman to have a baby at the time.

They carried out this huge survey of mothers

and ended up recording the birth of nearly every baby

born in England, Scotland and Wales in one week.

That was nearly 14,000 babies.

The questions they asked these women

are very different than the ones we might ask today.

They sound really old-fashioned now.

They asked them things like,

"During pregnancy,

did you get your full extra ration of a pint of milk a day?"

"How much did you spend on smocks, corsets,

nightdresses, knickers and brassieres?"

And this is my favorite one:

"Who looked after your husband while you were in bed with this baby?"

(Laughter)

Now, this wartime study actually ended up being so successful

that scientists did it again.

They recorded the births of thousands of babies born in 1958

and thousands more in 1970.

They did it again in the early 1990s,

and again at the turn of the millennium.

Altogether, more than 70,000 children have been involved in these studies

across those five generations.

They're called the British birth cohorts,

and scientists have gone back and recorded more information

on all of these people every few years ever since.

The amount of information that's now been collected on these people

is just completely mind-boggling.

It includes thousands of paper questionnaires

and terabytes' worth of computer data.

Scientists have also built up a huge bank of tissue samples,

which includes locks of hair, nail clippings, baby teeth and DNA.

They've even collected 9,000 placentas from some of the births,

which are now pickled in plastic buckets in a secure storage warehouse.

This whole project has become unique --

so, no other country in the world is tracking generations of children

in quite this detail.

These are some of the best-studied people on the planet,

and the data has become incredibly valuable for scientists,

generating well over 6,000 academic papers and books.

But today I want to focus on just one finding --

perhaps the most important discovery to come from this remarkable study.

And it's also the one that spoke to me personally,

because it's about how to use science to do the best for our children.

So, let's get the bad news out of the way first.

Perhaps the biggest message from this remarkable study is this:

don't be born into poverty or into disadvantage,

because if you are,

you're far more likely to walk a difficult path in life.

Many children in this study were born into poor families

or into working-class families that had cramped homes or other problems,

and it's clear now that those disadvantaged children

have been more likely to struggle on almost every score.

They've been more likely to do worse at school,

to end up with worse jobs and to earn less money.

Now, maybe that sounds really obvious,

but some of the results have been really surprising,

so children who had a tough start in life

are also more likely to end up unhealthy as adults.

They're more likely to be overweight,

to have high blood pressure,

and then decades down the line,

more likely to have a failing memory, poor health and even to die earlier.

Now, I talked about what happens later,

but some of these differences emerge at a really shockingly early age.

In one study,

children who were growing up in poverty

were almost a year behind the richer children on educational tests,

and that was by the age of just three.

These types of differences have been found again and again across the generations.

It means that our early circumstances have a profound influence

on the way that the rest of our lives play out.

And working out why that is

is one of the most difficult questions that we face today.

So there we have it.

The first lesson for successful life, everyone, is this:

choose your parents very carefully.

(Laughter)

Don't be born into a poor family or into a struggling family.

Now, I'm sure you can see the small problem here.

We can't choose our parents or how much they earn,

but this British study has also struck a real note of optimism

by showing that not everyone who has a disadvantaged start

ends up in difficult circumstances.

As you know, many people have a tough start in life,

but they end up doing very well on some measure nevertheless,

and this study starts to explain how.

So the second lesson is this:

parents really matter.

In this study,

children who had engaged, interested parents,

ones who had ambition for their future,

were more likely to escape from a difficult start.

It seems that parents and what they do are really, really important,

especially in the first few years of life.

Let me give you an example of that.

In one study,

scientists looked at about 17,000 children who were born in 1970.

They sifted all the mountains of data that they had collected

to try to work out

what allowed the children who'd had a difficult start in life

to go on and do well at school nevertheless.

In other words, which ones beat the odds.

The data showed that what mattered more than anything else was parents.

Having engaged, interested parents in those first few years of life

was strongly linked to children going on to do well at school later on.

In fact, quite small things that parents do

are associated with good outcomes for children.

Talking and listening to a child,

responding to them warmly,

teaching them their letters and numbers,

taking them on trips and visits.

Reading to children every day seems to be really important, too.

So in one study,

children whose parents were reading to them daily when they were five

and then showing an interest in their education at the age of 10,

were significantly less likely to be in poverty at the age of 30

than those whose parents weren't doing those things.

Now, there are huge challenges with interpreting this type of science.

These studies show that certain things that parents do

are correlated with good outcomes for children,

but we don't necessarily know those behaviors caused the good outcomes,

or whether some other factor is getting in the way.

For example, we have to take genes into account,

and that's a whole other talk in itself.

But scientists working with this British study

are working really hard to get at causes,

and this is one study I particularly love.

In this one,

they looked at the bedtime routines of about 10,000 children

born at the turn of the millennium.

Were the children going to bed at regular times,

or did they go to bed at different times during the week?

The data showed that those children who were going to bed at different times

were more likely to have behavioral problems,

and then those that switched to having regular bedtimes

often showed an improvement in behavior,

and that was really crucial,

because it suggested it was the bedtime routines

that were really helping things get better for those kids.

Here's another one to think about.

In this one,

scientists looked at children who were reading for pleasure.

That means that they picked up a magazine, a picture book, a story book.

The data showed that children who were reading for pleasure

at the ages of five and 10

were more likely to go on in school better, on average,

on school tests later in their lives.

And not just tests of reading,

but tests of spelling and maths as well.

This study tried to control for all the confounding factors,

so it looked at children who were equally intelligent

and from the same social-class background,

so it seemed as if it was the reading which really helped those children

go on and score better on those school tests later in their lives.

Now at the start,

I said the first lesson from this study

was not to be born into poverty or into disadvantage,

because those children tend to follow more difficult paths in their lives.

But then I said that parenting matters,

and that good parenting, if you can call it that,

helps children beat the odds

and overcome some of those early disadvantages.

So wait,

does that actually mean, then, that poverty doesn't matter after all?

You could argue it doesn't matter if a child is born poor --

as long as their parents are good parents, they're going to do just fine.

I don't believe that's true.

This study shows that poverty and parenting matter.

And one study actually put figures on that,

so it looked at children growing up in persistent poverty

and how well they were doing at school.

The data showed

that even when their parents were doing everything right --

putting them to bed on time

and reading to them every day and everything else --

that only got those children so far.

Good parenting only reduced the educational gap

between the rich and poor children by about 50 percent.

Now that means that poverty leaves a really lasting scar,

and it means that if we really want to ensure the success and well-being

of the next generation,

then tackling child poverty is an incredibly important thing to do.

Now, what does all this mean for you and me?

Are there lessons here we can all take home and use?

As a scientist and a journalist,

I like to have some science to inform my parenting ...

and I can tell you that when you're shouting at your kids

to go to bed on time,

it really helps to have the scientific literature on your side.

(Laughter)

And wouldn't it be great to think

that all we had to do to have happy, successful children

was to talk to them, be interested in their future,

put them to bed on time, and give them a book to read?

Our job would be done.

Now, as you can imagine,

the answers aren't quite as simple as that.

For one thing, this study looks at what happens

to thousands and thousands of children on average,

but that doesn't necessarily say what will help my child or your child

or any individual child.

In the end, each of our children is going to walk their own path,

and that's partly defined by the genes they inherit

and of course all the experiences they have through their lives,

including their interactions with us, their parents.

I will tell you what I did after I learned all this.

It's a bit embarrassing.

I realized I was so busy working,

and ironically,