‘A cyborg, or whatever word you want to use – a humanoid AI doesn’t require food. None of the machines I make would have any use for food. Look at your toy dog. Not that they would be given any regardless, since there’s barely enough to feed people. As you know, that’s the reason pets are illegal.’ I could tell she wanted to stand and pace while giving a fascinating lecture on the subject, but I wasn’t going to let that happen. I needed to keep my agenda in focus.

‘So why the goo?’

‘If I wanted him to pass as human, he had to eat something,’ said Mum. ‘Hence the goo, which wastes no foodstuffs.’

‘Klinsmann’s disease?’

‘My invention.’

‘It’s on the internet. I’ve looked it up.’

‘Of course it is. I made sure of it.’

I nodded.

‘How does he function then? I eat food, which is converted to energy. Where does Aiden get his?’

‘It’s a good question.’ I really wanted to tell Mum to go to hell. This wasn’t a lecture theatre and I wasn’t a student to be patted on the head for being a bit bright. But I had to keep my emotions in check. If I lost control of them, then I would lose everything. There’d be time for emotions later. ‘In fact,’ Mum continued, ‘your brain requires less energy than used to be consumed in one of those old-fashioned bulbs in lamps. Nearly all your energy goes into metabolism and the human body is a shockingly inefficient system. Put simply, Aiden’s body is efficient and he runs on renewables – the sun and the wind basically.’

‘What actually happens when Aiden goes into that clinic if it’s got nothing to do with cleaning his intestines?’

‘I told you. Modifications to his appearance to give the illusion of growth, and checking out the artificial neural networks that enable his learning capabilities. Tweaking those if necessary. Just recently, when his behaviour changed after the skull trauma, I tried to alter the algorithms back to the original setting, remove any possibility of violence. I failed. I tried so hard, but I failed.’

‘What would happen if Aiden never went back to the clinic?’

Mum frowned.

‘Well, he wouldn’t grow, obviously. He would stay the same, looking like a thirteen-year-old boy for … well, forever, I suppose.’

‘It’s interesting,’ I said. ‘Whenever you talk about Aiden, you say “he”. You might try to be the cold, hard scientist, but you see Aiden as a person. You see him as your son.’

There was a flash in Mum’s eyes at those words, but it was difficult to read it. She steadied herself and it obviously took an effort of will.