The most convincing argument against early parenthood is that you are in a relationship that is likely to fall apart before that child grows up.
The thing I care about is my weight - I'm as fanatical about it as a member of Girls Aloud. I weigh myself every morning. I know exactly what I want to be - 82kg - and I try to stick to it.
My principal motivation is supporting my family, which is not a bad reason for getting up in the morning. That's always been my motivation - to take care of the people who rely on me.
I box for four hours a week and my diet is pretty healthy.
I have found having my dad as my North Star has worked well for me.
When he was born, I looked at my little boy and felt an unconditional love I never knew was inside me. As he grew, and I watched him stagger about, squeak his first words, and turn into a beautiful little boy, that feeling did not change.
Largely this is a class thing - writers tend to be cosseted little middle-class kiddies who think that the world owes them a royalty cheque. But just doing it - being in your room for years on end, locked in your head, alone with invented ghosts - it weakens and softens the body. And I know I can't just live in my head.