Jad Abumrad

Well, there's the Boston one.

There's two in North Carolina.

She would ultimately discover one in Richmond, Virginia, one in Philly.

Hey, I'm Jad, I'm Rod.

I'm Robert Krulwich.

This is Radio 1.

Where are we at this point?

Okay, yeah, so Sarah Gray, when we left her, she was standing in a research office in Boston and feeling good.

Yeah.

She's gotten this rose of a success.

And so after that, her and Ross get in a car and head down south.

To track down Thomas's liver and a bit of his blood.

Because it turns out that in the delivery room, right after both twins were born, nurses had withdrawn a little bit of chord blood from both twins, sent it off to Duke,

where researchers were studying the disease that killed Thomas, anencephaly.

She says they walked in.

They met all these different researchers who all seemed really excited about her twins' blood samples.

After they all took the tour, one of the researchers even told them that they had compared Thomas' blood to Callum's.

That's so interesting.

So they began identical, but then somehow in utero, a thousand little changes crept up between them.

It's possible that a few of those changes might one day explain the disease.