Jack stares at me blankly. 'A what?' he asks. I choke back the laugh. 'A boy. You know? A Y-chromosome holder? You don't seem to notice them as much as you do the X-carriers.' 'What are you talking about?' Jack asks, 'A boy? She's just a kid.' I hesitate, wondering how Jack is only just doing the maths on this one now. 'She's seventeen. She's not a kid anymore.' Jack looks like he's about to go all Incredible Hulk and burst out of his clothes before rampaging through the bar. He jumps off the stool. 'If any boy ever lays a finger on my sister, I'm going to kill him,' he says. Again I stare at him in silence, thinking of all the girls Jack has laid fingers and much more of his anatomy on besides. Poor Lila. If she ever wants to have a shot at a normal life, as in one that doesn't require a vow of celibacy, she needs to stay in London.