What I imagined doesn't require anti-gravity beams or anything too spectacular, just advances in analysing different genes, finding out what they can do and recombining them.

Holman's world is a worst case scenario but it's healthy to examine extreme possibilities. If the technology that is used for genetic enrichment in Genus had been distributed equitably, across society, it could have been nirvana, a great world where people don't fear the diseases that we die from. The problems that arrive are more to do with resource hording than technology itself.

When I start writing for the day, I usually read aloud the chapter I'm working on. It gets me into it and illuminates mistakes. I'm very rhythm conscious and I do enjoy repetition.

There are very good evolutionary reasons for having religion. From early human history we have evolved a need to see God. We have a perception of ourselves and in order for that to be a true perception we have to believe in a soul within us.

We have this sense that there's something bigger than us, above and beyond. If you take away the idea of God, you need to replace it with a shared moral code. Otherwise, everybody becomes very self-centred and materialistic.

I debated whether or not to pin the setting down to a particular date but in the end I decided to leave things vague. It depends how fast technology improves.

I wanted to write a book that imagined where advances in the study of genetics might lead us. Holman was the first character who came to me: I envisaged the misshapen offspring of beautiful, wealthy parents. Then I realised that he bore a striking resemblance to Toulouse-Lautrec. I developed that, made Holman an alcoholic who lives among hookers, an artist tortured by his disability.