‘Time will tell, I suppose,’ said Matt. ‘But I have to find out the facts. It was me who made the decision to have children. Well, me and Kate.’

‘Have you talked to Kate about it?’

Matt ran a hand across his face. ‘I need to know what to tell her first.’

‘When you were looking up all this information on the internet, did you come across any advice? What do they say you should do?’

‘Talk to a psychiatrist.’

‘And that’s what you’re going to do, right?’

Matt sighed. ‘According to some of these websites, the genetics of mental illness will be much better understood in twenty years’ time. But there isn’t much chance of research having practical applications within five years – when it would be useful to me. Or useful to you, Ben.’

‘I’m not planning on having kids any time soon.’

‘You’re past thirty. You won’t want to wait that much longer. Men have a body clock, too.’

‘If you say so.’

‘What about that girlfriend of yours?’

‘Liz? We’re just . . . Well, we’re just going out together, that’s all.’

Matt raised his eyebrows and gave him a sceptical glance.

‘What?’ said Ben.

‘Nothing. I just think you’ve been different since you got together with her.’

‘No, I haven’t.’

His brother snorted. ‘Be that as it may. In the end, Ben, you’ll have to face the fact that no one can tell you whether a child of yours will be healthy, or vulnerable to schizophrenia.’

‘That’s one thing I’m not going to worry about,’ said Ben firmly.

A few minutes later, he left his brother in the office and went out into the passage that ran through the centre of the house. When he was a child, the passage and stairs had been gloomy places. He remembered dark brown varnish, and floorboards painted black alongside narrow strips of carpet that had lost its colour under layers of dirt.

Things were very different now. There were deep-pile fitted carpets on the floor, and the walls were painted white. Or maybe it was some shade of off-white. Kate would know the exact name from the catalogue. The wood had been stripped back to its original golden pine and there were mirrors and pictures to catch the light.

Reluctantly, Ben turned and looked up the stairs. At the top, he could see the first door on the landing, the one that had been his mother’s bedroom. After the death of his father, she had gradually deteriorated until the family could no longer hide from each other the fact that she was mentally ill.

Isabel Cooper had been diagnosed with chronic schizophrenia, and finally the distressing incidents had become untenable, especially with the children in the house. Ben shuddered at the memory. He never wanted to witness anything like that, ever again.