Thanks for downloading this edition of More or Less from Radio 4.

You can find out more about the program at bbc.co.uk forward slash More or Less.

But on with the program, here's Tim Halford.

Hello and welcome to More or Less.

We're like the levers of inquiry only for numbers and with better jokes.

In this week's program, after all the detail from the autumn statement,

we try to distill the message to get the important big picture on the economy.

And we'll ask whether everything we know about African economies is wrong.

And we will return to the topic of Lego, but with a different twist.

With Lego, you have some basic blocks and some ways of sticking them together.

And then you can build anything and maths is the same.

But first, in light of the royal pregnancy, there's been a lot of speculation about

what acute morning sickness tells us about the chances of having twins.

Newspapers and broadcast media have raised the possibility and opportunist bookmakers

have slashed the odds on the birth of twins.

This seems incredibly premature, so early in a pregnancy.

But the way the numbers have been used or abused makes a broader statistical point.

We thought that the only way to cover the experience of pregnancy and morning sickness sensibly

is to have two men discuss the issue, so I'm joined by somebody who isn't likely to suffer from either condition.

Evolutionary biologist, TV's Jan Wong.

I began by asking him whether the media were right to claim

that acute morning sickness raised the chances of having twins.

...