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.

More and more NFL players have been willing their bodies to science so that their brains can be studied even if they die of other causes.

We are all born with an innate understanding of interpersonal equity - the idea that if you lend me your rake today, I'll respond in kind when you come to borrow my shovel tomorrow. Or nearly all of us are born with that. Psychopaths aren't.

Older fatherhood isn't all bad: testosterone rates drop about 1% per year as men age, making them less reactive and more patient, and a professionally established middle-aged man is likely to have more time and money to devote to his kids than a twenty-something who's just getting started.

Jellyfish serve as a model for bioengineers for the same reason yeast were once so valuable to geneticists: they're simple to deconstruct.

There's a sort of sibling moratorium when you're establishing yourself as an adult. So much of your energy has to be focused on other things like work and kids. But when people become more settled, siblings tend to regroup because now you're building a new extended family.

Your parents leave you too soon and your kids and spouse come along late, but your siblings know you when you are in your most inchoate form.