Every batch of sperm represents an opportunity for genetic typos - called de novo mutations - to be passed on. A 20-year-old man and woman will each pass on about 20 de novo mutations to a baby they conceive. By the time the couple is 40, a woman's total has remained at 20, while a man's has jumped to 65 - and it keeps climbing from there.

If we were a culture of high-risk alcoholics, and suddenly we had Jack Daniels piped into our houses, we would be feeding that fire. Social networking, and the internet as a whole, seems to have simply landed in an extremely fertile place in an extremely fertile time in history, when we all have these narcissistic tendencies anyway - you can go further back into the self-esteem movement, and Dr. Spock, and the 'everybody gets a ribbon at the track meet' sort of thing, which preceded the internet - and then you drop the internet into the middle of this, and we've all gone haywire.

Everybody loves to spend money at least some of the time - because everybody loves the stuff you can buy with it. The key to the pleasure level of any transaction is the balance between the pain of the payment and the reward of the purchased object.

There's only one thing harder than living in a home with an adolescent - and that's being an adolescent. The moodiness, the volatility, the wholesale lack of impulse control, all would be close to clinical conditions if they occurred at another point in life. In adolescence, they're just part of the behavioral portfolio.

Toxins love to get you while you're young. Lead, mercury, secondhand smoke and sundry other environmental nasties do a lot more damage when tissue is immature, vulnerable and growing than when it's mature and comparatively fixed.

Marriage is a lot of things - a source of love, security, the joy of children, but it's also an interpersonal battlefield, and it's not hard to see why: Take two disparate people, toss them together in often-confined quarters, add the stresses of money and kids - now lather, rinse, repeat for the rest of your natural life. What could go wrong?

Is there anything sadder than the foods of the 1950s? Canned, frozen, packaged concoctions, served up by the plateful, three meals per day, in an era in which the supermarket was king, the farmer's market was, well, for farmers, and the word 'locavore' sounded vaguely like a mythical beast.