It's 40 years since in vitro fertilization or IVF revolutionized the way humans procreate.

British-born Louise Brown was the world's first test tube baby.

Her birth astonished societies around the world.

It challenged our deeply ingrained

notions of kinship, parenthood and human reproduction. But it also opened the doors to

couples who would otherwise have remained childless.

When we started out, every time we had a pregnant woman, no matter how many we have treated,

was an absolute victory.

In part one, we met the new types of families created by artificial reproductive technology,

twins born using frozen sperm from a dead man.

Let's use IVF to bring Prasamash back. They're his cells. This would be him.

The embryos left on ice only to be born years later.

So Saschios conceived in 2014 and then frozen and this is a picture of her when she was

thawed last year just before the transfer.

I'm Kropa party and in part two of the changing face of procreation on the BBC World Service

I am looking at what's next for the assisted reproductive technology sector.

Inf fertility isn't solely a rich world's problem. So how can we spread the

benefits of IVF? What clinical innovations can we expect next? And what will happen

to social structures once age and relationship status are no longer

barriers to parenthood. It's dinner time at Pia Krona's house and bubbling on the slow cooker is spaghetti bolognese.

Her two-year-old daughter, Sarah, plays with her friends in the lounge

switching her attention between kids TV and a giant space hopper. It's all very normal, but in fact this gathering is part of a growing subculture of family life,

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