SACRAMENTO, Calif. — Shirley Berger holds a photo of herself taken at Venice Beach, Calif., in 1960. She's about 20 in the picture and looks like Elizabeth Taylor: the same thick eyebrows and upturned nose. She's on her stomach, holding a cigarette. A layer of her dark curly hair covers her head.

“My hair was so thick, you couldn't see through it at all,” Berger said. “I had a ton of hair.”

At 58, 10 years after she hit menopause, her hair started to thin and fall out. She bought a wig, but she hated how it felt.

She goes to the hairdresser once a week now for help hiding the thin spots. At restaurants, she maneuvers herself out of the way when waiters come to the table so they can't see the top of her head. And she sleeps on satin pillowcases to avoid snagging her hair.

“I'm not sure I understand why men can get away with aging,” said Berger, who is now 70.

Sitting in her Carmichael, Calif., home, she splays old photos across her kitchen table. A few feature the sky-high hairdo she wore in 1976.

“It's scary because all of a sudden you knew, just looking in the mirror every day, you knew you were aging. ... I would give anything if I had not lost my hair,” she said.

Aside from menopause, the American Academy of Dermatology reports that 30 million women in the United States are losing their hair due to genetic factors. Thyroid disease, medication side effects and diet also can cause it.

It's estimated that one in four women experiences thinning hair.

“With some, it has to do with dramatic changes in their life: surgery, delivering a child ... having a very severe illness,” said Pamela Prescott, an endocrinologist at the University of California-Davis Medical Center. “Sometimes, it's what we do to our hair, the styling, dyeing, straightening.”

Stress, Prescott said, can have a major effect on hair growth. And for some, losing their hair gives them more reason to stress than the actual medical cause.

“It was very traumatic,” said Kristy DeVaney, who lost all her hair after having a negative reaction to the common antibiotic minocycline. “It was very hard to deal with for a very long time. ... I kept thinking, ‘What do people think of me? What do I think of myself? I'm an ugly bald person.' It's probably the worst thing I've ever been through.”

Maxine Craig, an associate professor in the Women and Gender Studies program at UC Davis, has researched just how much hair means to women.

It means a whole lot.

“Hair is seen as a marker of gender identity,” Craig said. In most Western cultures, short hair or no hair represents masculinity, and long hair represents femininity.

“These are social codes that we all learn and learn deeply,” Craig said. “When a woman loses her hair, she may feel that she is losing something that identifies her as a woman.”

Girls who cut their hair short and men who grow their hair out are considered rebels — people who want to resist the social code and be defiant.

“Women who do not attempt to conform to beauty norms are seen as somehow problematic,” Craig said. “Girls start hearing at a very young age that their looks are important ... and women are constantly getting evaluated on the basis of their appearance.”

Kusum Jain began losing her hair last October when she fell ill during a family trip to India.

“I got really worried so I started saving my hair,” she said. “I said, ‘If I'm going to get extensions, I might as well get it from my own head.'” She still has the hair in a bag, she said. Just in case.

For women more adamant about replacement, there are specialists like Edward Thacker. He runs a hair treatment center off Watt Avenue called Natural Look Transitions. In the sleek white waiting room, a television perpetually runs hair advertisements.

Thacker is not a doctor. He went into hair styling in the 1980s but got involved with hair loss treatments when his mother and sisters began losing their hair.

He provides people with hairpieces, laser treatments and integration wigs, which look like fishing nets with an extra layer of hair that clients can comb through their real hair.

He recalled a client who barely spoke on her first visit. She sat quietly, hands in her lap, shoulders shrugged. After receiving treatment, Thacker said, her personality changed. She walked more confidently, was more outgoing and she'd say hello.

“Imagine you're the brightest, most talented person, and you've got it all together, but you won't go out and present yourself because you're afraid of your hair,” he said.

Thacker's clients pay from $800 to $2,000 for custom hairpieces, and maintenance can run up to $50 to $150 a month.

“This is what the customers want,” he said. “We've been beaten down by the beauty industry and they've won.”

Berger is trying to delay wearing any type of hairpiece, even hats, for as long as she can.

“I don't like anything on my head,” she said.

Although she worries what will happen to her if she goes completely bald, her husband, Max, said he wouldn't mind.

“I'd call her cue ball, I guess,” he said, chuckling. “But I doubt it would bother me much.”