From the outside, Holly Finn certainly looks fertile.

With shoulder-length dark hair, smooth skin and a slim but curvaceous figure, the San Francisco-area writer could be any young mom with a baby on her hip.

But at 43, Finn says, her ovaries know better — and she would have, too, if not for what she believes is society’s widespread ignorance about infertility.

“I really feel that there are important pieces of information that don’t get passed along,” says Finn, who has now tried for four years to conceive through in-vitro fertilization. “I actually think it’s quite a brutal dishonesty.”

Most women aren't taught — and don't learn — basic facts about fertility and aging, says Finn, author of the e-book “The Baby Chase." Instead, celeb moms the likes of Salma Hayek (a baby girl at 41), Marcia Cross (twins at 44) and Mariah Carey (twins at 41) make being an older mom look easy — and glamorous.

“It’s not that we’re stupid,” she says. “It’s that we’ve been misinformed.”

As proof, she points to a new fertility awareness survey sponsored by biopharmaceutical firm EMD Serono Inc., with investigators from RESOLVE, the National Infertility Association. It was presented at the American Society of Reproductive Medicine’s recent annual meeting.

The poll of 1,000 women ages 25 to 35 who had talked to doctors about fertility found that participants could correctly answer seven out of 10 basic questions less than half the time. The Fertility IQ 2011 Survey found that women were wrong most often about how long it takes to get pregnant — and about how much fertility declines at various ages.

“We were not at all surprised,” says Barbara Collura, executive director of RESOLVE. “This is what we experience every day.”

Most women simply don’t realize that at 30, a healthy woman has about a 20 percent chance of conceiving per month and by the time she reaches 40, her odds drop to about 5 percent, Collura said.

Trending stories,celebrity news and all the best of TODAY. This site is protected by recaptcha

At what age did you have your first child? Or when do you plan to? Tell us on Facebook

Instead, many of those surveyed thought that a 30-year-old woman would have a 70 percent chance of conceiving and that a 40-year-old’s chances could approach 60 percent.

They also believed that a 20-year-old woman might get pregnant in less than two months of unprotected sex, rather than the five months that is the average.

“It’s basic biology and basic knowledge of how age impacts your fertility if you’re a woman,” says Collura.

But most women aren’t getting those basics until it’s too late, said Dr. William Schoolcraft, medical director of the Colorado Center for Reproductive Medicine in Denver and two other locations.

"They don't even come in for fertility treatment until they're literally in their 40s," he said. "Some come in and they have run out of time."

In a country where sex education focuses primarily on avoiding pregnancy and preventing sexually transmitted diseases, most women believe that having a baby is inevitably easy.

But that neglects the reality that infertility affects some 7.3 million women in the United States, or 12 percent of the child-bearing female population, and about 1 in 8 couples, according to the Centers for Disease Control and Prevention. After about age 35, fertility plummets, Schoolcraft said.

So when women decide they want to get pregnant and can’t, they’re stunned. Some of the shock is because of advances in health and beauty that allow women to look — and feel — younger, even as their reproductive systems march on.

“People kind of think now at 40 what they used to think at 30,” Schoolcraft said. “People do yoga and they run and they do all these healthy things. They assume that means ‘I’m not aging.’ But their eggs don’t know that.”

Part of the disconnect is because of advances in infertility treatment, which have helped boost the rates of births among women in their 40s, even as rates have dropped for younger moms. Between 2008 and 2009, births in women aged 20 to 24 reached a record low, falling 7 percent. At the same time, the rates for women aged 40 to 44 jumped 3 percent and births to women older than 50 climbed 5 percent.

Those numbers are exemplified by a series of high-profile births in older celebrities, including icons such as Kelly Preston (son at 48), Holly Hunter (twins at 47) and Jane Seymour (twins at 44.)

The famous mamas may or may not disclose whether they’ve used fertility aids, such as IVF or donated eggs, says Schoolcraft. That further contributes to the notion that it’s never too late to have a baby. “It sends the message, if she can do it, then Miss Healthy Boring Me, I won’t have any trouble at 41 or 42,” Schoolcraft says.

The trouble is, such thinking can cheat a woman out of her options, Collura says. It’s one thing to postpone children in order to pursue education or a career, fully knowing it might be more difficult to get pregnant later. It’s another thing to be surprised by infertility.

“This is not about empowering women and women’s rights,” she says. “This is about science and biology 101.”

That is precisely Holly Finn’s point. She wishes she had realized earlier the effects that endometriosis and age might have on her ability to conceive. If she had her way, she’d tell women ages 26 to 34 one thing: "Start having babies now."

After eight unsuccessful cycles, Finn is taking a break from IVF therapy, but she plans to pursue other infertility treatments or different paths to parenthood in the future.

“Giving up hope is almost impossible,” Finn says.

Follow @JoNel_Aleccia