we can transfer heredity through the substance of DNA.

It's possible for a lot of people to become successful.

You have to have the right genes.

For the first time, scientists have successfully repaired a faulty gene in human embryos.

They used a process known as gene editing.

It could help eliminate deadly genetic diseases but some say it's too much like playing God

and opening a dangerous Pandora's Box.

If this was going to be your baby would you have gone ahead with this?

This story begins in the 1850s in a small monastery.

And with this monk, Gregor Mendel.

While he's experimenting with pea plants, he identifies that traits like color and height

pass from one generation to the next.

He's the first to establish the principle of inheritance.

After Mendel dies the other monks in the abbey take the notes of his astonishing discovery,

put them into a pile, and burn them.

Well there's no question that Mendel was ahead of his time.

I guess you'd say the scientific community was not ready to hear what he was saying.

It's fraught with anxiety because there's this idea that you may be playing God

you may be trying to determine the future and taking control of things that people should

not have control over.

So other scientists rediscover what Mendel already knew and in 1905 the word 'genetics'

appears for the first time.

Research on DNA is one of the great new challenges in science.

Skip forward to 1953 and scientists at Cambridge University

discover that DNA has a double helix structure.

DNA is a code.

The structure of DNA showed exactly how that code was put together.

Once you knew what the structure was, you could begin to introduce other chemicals

you could take things apart, you could put them back together.

All those types of things you could suddenly start studying.

In the 1970s American biochemist Paul Berg isolates DNA from different sources

then he cuts and splices them together.

The result is recombinant DNA.

He writes a letter about the

"potential biohazards" of what he's just discovered.

All gene editing experiments stop until 1975

and the Asilomar Conference in California.

A group of around 140 scientists, physicians and lawyers

come up with practical and ethical guidelines.

It was almost like a nuclear treaty for biotechnology.

Scientists were looking at recombinant DNA with the idea of doing positive things.

Somebody else could take these and start using them

to make poisons to make bioterrorist weapons.

So they felt like the time it was time to take a step back, create some rules

and that's what they did.

By 1994 the first genetically engineered food hits the shelves.

Controversy is swirling around an updated variety of the humble tomato.

It's called the Flavr Savr.

2012 is the year of a landmark discovery.

It's called CRISPR

CRISPR

CRISPR Cas9

There's a dispute about who actually discovered this tool for editing the human genome.

But now scientists can cut out faulty sections of DNA and replace them with healthy ones.

It's cheap, it's easy to use.

I've watched people use CRISPR in a neighborhood laboratory

and these were folks that were no more scientists than you and I.

That that's exciting because that gives you all kinds of power to do experimentation.

The concerns are that people might use this say to increase the strength of their offspring

or to choose eye color, to try to affect personality.

The number of gene editing advances using CRISPR is growing worldwide

and soon China steps up its efforts to dominate the biotechnology sphere.

And in 2018 this happens.

Irresponsible, disturbing, inappropriate, that's how two of the inventors of a

gene editing tool are describing a Chinese scientist's experiment

that helped create genetically edited babies.

From what I've read he had relatively high-minded ideals about what he was doing and I think

his impression was that it was going to be welcomed.

The audience that he sat in front of was really pretty horrified and eventually

the Chinese government really started to turn against him.

The interesting thing is that every time a new technology comes along everybody talks

about it as though it's a Pandora's Box

and that these evils are going to fly out with a good.

And that is true.

There's always risk but that's the story of science.

The whole idea is to open up these boxes and to see what's inside.

And each time you open up a box, there's another box inside of it.

And that's going, what's going to happen with CRISPR is the revelations will continue and

the controversies will continue.

That's just the way science goes.