Jo Setchell

How do they gauge that?

Through smell.

So there's a link between the immunity genes and the smell of the animal,

And they're partly looking just for a good immune system, but they're really looking for a match between their immune system and the male's immune system.

Actually, this works both ways.

Males also base their mating decisions on the female's genetic makeup.

And in the end, the point is to make a better quality immune system in the baby.

Ah, so I think it's changed our understanding of humans in that we're not consciously aware of odour.

But we're very unconsciously aware of odour.

So it affects us enormously.

It brings back memories to us instantly.

But we don't necessarily think that we're influenced by it.

So perhaps what we know now about primates and other mammals has influenced what we know about humans.

In a way, possibly.

But there are other ways in which we also can pick up on our genes.

So one is in the odour that we have on our body.

Another is in the mouth when we kiss, for example.

So you might wear some fabulous perfume that is created to attract the opposite sex, but it

It won't take you as far as kissing.

We see lots of different sexual behaviours, so definitely, yes, both across species and within species.