Hair is a rich and powerful ornament. An evolutionary afterthought, hair remains an incessant distraction and obsession for humans. It was, after all, a blonde in Raymond Chandler’s “Farewell, My Lovely” who could make a bishop kick a hole in a stained-glass window.

For black women, the decision to relax - to straighten their hair - remains a delicate and vexing choice about their cultural identity. As Catherine Saint Louis reported in The Times, tightly coiled roots are seen as less acceptable to certain relatives as well as to the white establishment. Others embrace the Afro style as a visual cue for pride and dignity.

“For black women, you’re damned if you do, damned if you don’t,” Ingrid Banks, an associate professor of black studies at the University of California at Santa Barbara, told Ms. Saint Louis. “If you’ve got straight hair, you’re pegged as selling out. If you don’t straighten your hair,” she said, “you’re seen as not practicing appropriate grooming practices.”

All women have always felt an extra degree of cultural pressure to make their hair, all their hair, “normative.” Ms. Saint Louis reported in a separate article how women, starting in the 1920s, were exhorted by makers of hair-removal products to shave their underarms and their leg hair.

But now hirsute men are also finding themselves suspect. In order to seem more hygienic and attractive, they are removing hair from their chests, backs, armpits and, yes, their groins.

“It used to be a hallmark of male models and homosexuals,” Kat Fay, a senior analyst at Mintel, a market research firm, told Ms. Saint Louis about such “manscaping.” But now this sleek look, “the greatest dating weapon,” has spread to a broader range of men.

In late May, Gillette’s How to Shave Your Groin video ranked No. 3 on a list of the top online video ads compiled by Visible Measures, an Internet video measurement firm.

The epilation craze has even devoured eyebrows. The newest trend - in both sexes - is to get rid of eyebrows altogether, either by bleaching them into oblivion or by shaving them off, William Van Meter reported.

“There is an asexual element to no eyebrows. We are much more accepting of the ‘other’ nowadays. Removing eyebrows removes a degree of expression, which makes one look less human and more cerebral, maybe even mechanical. It’s an exercise in modernity,” Lauren Boyle, a fashion consultant, told Mr. Van Meter.

In some cases, however, hair is not about making a statement, but simply a question of keeping a healthy set of teeth. New research shows that because of a genetic mutation people with red hair need larger doses of anesthesia and often are resistant to local pain blockers, Tara Parker- Pope reported. As a result, redheads are twice as likely to avoid going to the dentist as people with other hair colors.

“Because they’re resistant, many redheads have had bad experiences,” Dr. Daniel I. Sessler, an anesthesiologist at the Cleveland Clinic, told Ms. Parker-Pope. “If they go to the dentist or have a cut sutured, they’ll need more local anesthetic than other people.” Talk about a bad hair day.