Every time C comes in from work, T has secured a new milestone of stairs, and I go, "Guess who climbed six stairs today. No, guess, guess!" and without fail, C will say: "Supervised?" "Well, yes of course he was supervised," I might say, or "No, I was actually in the cinema at the time, but he must have climbed them 'cause when I got back he was checking his emails," or "Why do you even leave him with me, if you think you have to ask a question like that?" depending on whether my dial is on Regular, Sarcastic or Angry. But I am always aggrieved, because at heart I think there is no safer place T can be than on my watch.

You read statistics about this, in rightwing newspapers: that children have the fewest accidents when they have their actual mothers looking after them. These articles used to make my blood boil, being evidently a means of guilt-tripping mothers who work. I am still infuriated, but underneath the fury is at least the consolation that, while society remains implacably, even increasingly, stacked against women for whatever decision they choose to make, if this outrageous slur turns out to be true, well, I'm all right, Jackettes. Pull up the ladder. T definitely won't fall on his face, because here I am, watching. Except he always does. Always on my watch. Is this a numbers game, that it's always my watch, so that's bound to be the time he falls over? Or am I just uniquely crap at watching?

I told you already about the time he fell off the bed at six weeks old, and that was definitely the worst. There is no noise as hideous as the gap between that thud and the wail, as you lie there thinking "I wonder what that ... oh no." Since then, he has fallen off the bed twice, and that is not counting the time he kind of slid off, appearing to be in control of the situation until halfway through. When he started learning how to stand up, I sat there, so help me, cheering him on, as he took his hands off whatever he was clutching and immediately fell backwards on to his head. I could not believe how stupid I was. I thought about banging my own head on the floor in penance. The only consolation I can draw from the entire situation is that, when they're too young to work out how not to fall over, they are too young to remember how bad you were at stopping them from falling over. I don't know whether that's so much a solace as just getting one over on him. I got one over on my tiny baby. That's one for my cute slogan T-shirt range.

Today, ironically, I was listening to a programme about what a terrible mother Madame Bovary was, lolling on the sofa congratulating myself inwardly on how T would never end up in a workhouse, when I forgot to close the child gate and he got up 12 stairs, all the way to the bathroom, unsupervised. He didn't hurt himself (honest) but he did turn round with a look of unmappable triumph that was both cute and profound, like he had vanquished not only the physical universe but also all the rules standing between him and his dreams of loo roll. I'm reading too much into this, aren't I? If I just watched properly, I wouldn't have to concoct these elaborate advantages to the fact that I wasn't watching properly.

I could carry on; it would be quite repetitive, I don't have any dramatic spills up my sleeve. And yet I persist in thinking I'm the best person for this job, even as I watch the evidence mounting to the contrary. Or rather, not watching. In fact, if you were going to do an unemotional safety assessment, you would put T in this order of care: first with C's mother, who is so alert I don't want to broadcast it in case the government tries to poach her and put her in charge of Sizewell B. Second, with S, my sister, who has a better nose for trouble. Third, an outside choice but I'll stand by it, with my youngest sister, Tams, who has the speedy reactions of a young person, coupled with the inertia of a student, so when she's watching T, she's never not watching. Because that would require her to swivel her studenty eyeballs. I will put me and C in joint fourth position. That should give us something to argue about over the weekend.