After donning a hairnet and face mask, Mango met up with Charlie in Radical Cake’s employee break room. Since her fresh start was underway, Charlie decided to be adventurous and try black coffee. But even with three sugars it still tasted like battery acid. She thought throwing it away might offend and hid a grimace every time she swallowed.

Mango had made Charlie a series of lesson plans, like the ones she did for her groups at Maker’s Yard. After ensuring Development Kitchen 2 was locked from inside, Mango showed Charlie a printed copy of a case file from which she’d blanked the names.

‘Patient Q is thirty-two years old,’ Mango began as she sat at a table facing Charlie. ‘To help maintain security for my operation I don’t meet clients directly. I use a retired nurse, who consulted with him in Anaheim a couple of weeks back. Patient Q is a single man who’s made a lot of money with an online food business. But he lacks confidence and feels that his body isn’t attractive. He’s got pale skin with almost no pigmentation; he’s also a classic ectomorph. Do you know what that is?’

‘Scrawny?’ Charlie said.

‘Basically,’ Mango agreed, smiling and nodding. ‘An ectomorphic person is characterised by a slim body with little muscle mass. Most ectomorphs don’t bulk up when they do strength training. So, after some discussion, I’ve agreed to edit two gene groups.

‘One set of changes will affect melanin production and darken patient Q’s skin. The second will change muscle fibres and increase muscle mass. It’s a good example of a therapy that requires skilful patient matching. People with heavy musculature have also evolved heavy bones and strong tendons. But if you add Olympic muscle to a ninety-pound weakling, they end up with joint pain and injuries.’

‘But most gene therapies are reversible?’

‘They are,’ Mango agreed. ‘But every alteration carries a chance of a mistake, and increases the risk of mosaicism.’

‘Oh, I read about that yesterday afternoon,’ Charlie said.

Mango smiled. ‘Show me what you’ve got, then!’

Charlie felt the pressure and turned a touch red. ‘Each course of gene therapy targets and alters cells using a transmission vehicle such as a targeted E. coli virus, or stem-cell injection. But even after several courses of gene therapy, a tiny percentage of your original DNA will probably remain. Having two variants of the same cell type in the body can confuse the immune system into thinking one type is a disease, and the body starts attacking its own cells. Also, for reasons nobody understands yet, it gets more likely when you switch genes back and forth.’

‘Not bad,’ Mango said, satisfied with her recruit.