Older siblings get more total-immersion mentoring with their parents before younger siblings come along. As a result, they get an IQ and linguistic advantage because they are the exclusive focus of their parents' attention.

Kids are anarchy writ large.

The best you can sometimes do is learn to take a breath, count to ten and simply accept that try as you might, no, your husband will never, ever learn not to drop a wet towel on the bed. That acceptance too counts as resolving a fight.

What makes spinal-cord injuries as devastating as they are is that everything about them plays out in absolutes: they are instantaneous, utterly disabling and horribly permanent.

The brain sits snugly inside the skull, but it's not a completely flush fit - there is still a layer of fluid between bone and soft tissue that serves as a natural shock absorber. Some shocks, however, can't be absorbed, and when the head gets clobbered too hard, the brain can twist or torque or rattle around inside its skeletal casing.

No one ever pretended that shopping for anything is a rational experience. If it were, would there be Fluffernutter? Laceless sneakers? Porkpie hats? Would the Chia Pet even exist?

Some of the most rewarding times my brothers and I have are when all of us get together, and we can see what we've been building genetically and culturally.