There's plenty to read about keeping your sanity while raising children, but it's all common-sense stuff about task division and taking breaks and the relentlessly repeated magic of date night with your spouse. What's missing is some 'tude.

Sisters have ways of socializing brothers into the mysteries of girls. Brothers have ways of socializing sisters into the puzzle that is boys.

Paul McCartney had a baby when he was 61; Rod Stewart was 66; Rupert Murdoch was a stunning 72. Not only does that mean they'll have less stamina than the average dad, that means they'll, well, check out a lot sooner too.

My own life has in some ways been a decades-long tour of the sibling experience. I have full sibs, I have half-sibs, and for a time I had step-sibs.

Introverts listen better, they assess risks more carefully, they can be wiser managers. It's not for nothing that the Silicon Valley billionaires are so often the retiring types.

Scarily, football helmets, which do a fine job of protecting against scalp laceration and skull fracture, do little to prevent concussions and may even exacerbate them, since even as the brain is rattling around inside the skull, the head is rattling around inside the helmet.

There's no such thing as downtime for your brain.