ON a recent Sunday afternoon, a monthly meeting convened around a long table in a Whole Foods cafeteria on the Upper West Side of Manhattan. As people settled in, the organizer plopped down a bag of potato chips and tackled housekeeping matters, like soliciting contributions. But she did not insist.

Almost two years ago, pregnant with my daughter, I paid my first visit to the Cambridge Birth Center.

When my parents married in 1977, women’s liberation was in full swing and my mother was a consciousness-raiser. She was about as likely to take my father’s name as she was to sport a veil at the wedding. She would remain Ms. Tuhus.

Last week, new guidelines for diagnosing Alzheimer’s defined a “preclinical” stage of the dreaded disease.

The coral reefs of Hawaii are enchanting: a full spectrum of brilliant colors, teeming with spiky urchins, striped damselfish, sluggish sea cucumbers, and hundreds of other creatures.