9 Months That Made You

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Across the

planet, four times

every second,

a new human is conceived

and an extraordinary

journey begins.

In just nine months,

a single cell no bigger

than a speck of dust

transforms into the most

complex organism on Earth.

extraordinary journey

we'll ever take.

And now, with the latest

biological science,

we can follow, week by week,

minute by minute,

the events that

shape and define us

long before we are born.

From each beat

of our heart,

to every finger

on our hands,

to our personality

how long we'll live.

Each moment will be

different for us all,

because the steps

and missteps along

the way

create variations that

make each of us unique

and ultimately human.

So, let's relive

the journey,

as we zero in on

the weeks, days,

even hours

of the greatest story

about humans ever told.

Right from the start,

it's a journey packed

full of surprises.

Who was born first?

Who's the oldest?

Me.

Then me.

Then me.

I'm the youngest.

One eight minutes

between each of us.

Holly, Jessica,

Ellie, and Georgie

are genetically identical.

From one egg and one sperm,

genetic instructions

somehow ended up building

not just one human life,

but four identical ones.

What happened is so unusual

that on our planet of

over seven billion,

there are just 70 like them.

64 million to one,

the odds of my pregnancy.

Yeah, that's the odds

of the pregnancy.

To actually go through it

and survive it was

one in billions,

he said.

These sisters'

story is exceptional,

the same wondrous events

that happen to all of us.

sperm and egg meet,

an extraordinary event

takes place.

Twenty-three chromosomes

in our father's sperm

fuse with 23 from

our mother's egg,

which together create

the first-ever edition

of the unique set of

genetic instructions

for a human being.

Twenty-four hours later,

cells miraculously

One cell becomes two.

Two becomes four.

Until around day five,

hundred interconnected cells

tightly bound together.

And it was at this point

that this story took

a dramatic turn.

It was sort of arms

and legs and it was

all a bit...

Incomprehensible, I suppose,

wasn't it? You couldn't...

Yeah.

I couldn't fathom

out what was what.

And then...

sonographer could find

out, either, could he?

he went a bit, um...

that's the right word.

And he said, "Right."

He said it's a multiple

pregnancy.

Um...

We sort of smiled,

thinking, twins,

boy, girl, happy ever

after sort of thing.

this is really serious.

There's four babies

in here."

Exactly what happens

to produce twins,

triplets, or quads is still

a complete mystery.

But one idea is that around

five days into the journey,

the vital connections that

usually hold cells together

could be broken.

And separate clumps of cells

behave independently.

This incredibly rare chance

event split one into four,

with each clump

going on to build

an entirely separate

yet identical human.

So, what's the best thing

about being a quad?

sisters in the world.

Having fun.

Not being alone

all the time.

Having people there.

Around to help you.

'Cause...

If I didn't have any

sisters, I'd be really

sad and lonely.

They can help you.

Quite honored...

Most of the time.

Apart from when

they're playing up!

your fault anyway!

Yeah, I guess so.

Holly, Jessica,

Georgie, and Ellie

are a marvel of nature

who defy all the odds.

the many twists and turns

that can happen along

the extraordinary journey

and defines us...

Long before we are born.

But going from

no children to four.

A massive jump.

Hi, girls!

Come in and say hi.

Come here.

Hi, filmers!

Hello.

Hello.

Just wanted to see you.

It's the end of

the first week

and this microscopic bundle

of cells is barely visible,

just a hundredth

of an inch across.

It now starts to

implant in the walls

of the mother's uterus

and at this vital time,

some momentous changes

are happening,

every single cell.

dramatically influenced

by the world outside

and by what a mother

happens to be eating.

Which we're learning

the length of our lives.

[man speaking in