This is ridiculous, I think. I was going to do her a favour! I was going to bring joy to that small child! I'm his hero, after all!

I look up, cautiously. The mother has relaxed and is staring at her fingers, trying to get some dirt off her ring. I look at the little lad.

Why shouldn't I entertain the little ones of this world? Are they so much less important than us? Are their ideas of any less value? Well, yes, but should that stop me making faces at them on trains? No!

And then I see his mum is staring at me again, hard. And I realise that once again I've been looking at her child for a little too long.

'But I was building up!' I want to shout. 'I was building up to the funny face!'

I can save this. I try to smile and raise my eyebrows in a nonthreatening way, and then I gesture at the kid, and I say, in as confident a way as I can, 'Nice little boy!'

The words hang in the air. People look up from their papers. I think about what I've just said.

I have been caught staring at a little boy on a train - twice! - and then loudly said three of the most sinister words I could.

I don't know what to do.

I do the funny face, but then realise I'm doing it to the mother and at the last second switch to the boy.

He does not look impressed.

I get out two stops early and walk home, avoiding the toyshop.

THE TEST

'So you did it?' asks Colin, amazed. 'You really did it?'

'I did, sir!' I say, importantly. 'I did!'

I had been a man. Faced my fears. Stood up to the paranoia of the age. Been for a sperm test.

Maybe, I think, that's why children have been viewing me differently recently. Maybe it wasn't the funny face. Maybe it was the test!

'What was it like?' asks Colin, eyes wide and full of respect.

'I will not speak of these things,' I tell him, calmly, like a gladiator might tell something to an overawed peasant. 'These things are not for gentlemen to discuss.'

'Sorry,' he says, embarrassed.

'You will learn in time.'

He nods his understanding and leans back in his chair.

But then he leans forward again.

'Does a nurse do it, or do you do it yourself?'

'Silence, Colin,' I say. 'You must walk this road on your own one day.'

I look away.

'I will have a packet of peanuts now.'