Story highlights Tanya Selvaratnam wrote the book "The Big Lie" about the "reality of the biological clock"

Despite what celeb magazines suggest, it's harder to get pregnant after age 35, she says

Selvaratnam: "We are the guinea pig generation for testing the limits of our fertility"

Blame it on the baby bump and our pop cultural infatuation with celebrity, but today, regular women have yet another reason to feel inadequate: motherhood.

In the past decade, for the celebrity set, babies have become as fashionable as Birkin bags. The media has fueled the fertility frenzy by outing every pregnant, or potentially pregnant, Hollywood starlet. But then there's more -- with every aspect of a celeb mom's glamorized pregnancy reported, from excessive weight gain to dramatic post-partum weight loss , regular women are fed a distorted depiction of pregnancy.

But perhaps nothing does a tragic disservice to women more than the media's coverage of those over-35 celebrities who seem to easily get pregnant whenever they choose, writes Tanya Selvaratnam in her new book, " The Big Lie: Motherhood, Feminism and the Reality of the Biological Clock ."

"For the celebrity set, babies have become as fashionable as Birkin bags," Wendy Sachs writes.

"One of the reasons I wrote the book was because I was frustrated by the conflicting messages and information out there," Selvaratnam said. "We see celebrities having kids seemingly without any problems and we have no idea what they went through. We see the end result, but not the struggle."

Ironically, motherhood has never been so chic at a time when so many women are struggling to get pregnant. The number of women between age 40 and 44 who remain childless has doubled in a generation; in 1976 it was one out of 10, by 2006 it was one in five, according to the U.S. Census

In Selvaratnam's deeply personal and provocative book, she shares her own journey of three miscarriages, multiple IVF treatments, cancer and the ultimate toll it took on her marriage. She explores the impact of delayed motherhood and the bad information that women receive, not only from aspirational celebrity images, but also from their own doctors.

Selvaratnam writes that after her first miscarriage at 37 years old, her OB-GYN told her that she still "had time" to get pregnant. So instead of rushing to a fertility center, she waited, and that was a serious mistake.

The "Big Lie," she writes is that women can do what they want on their own timetables. They can delay motherhood until they are emotionally and financially ready, secure in their careers and have found that perfect partner and if they have trouble getting pregnant, modern medicine will miraculously give them a child.

Forty may be the new 30, but our ovaries have not gotten the same makeover. Even with all the advances in reproductive technology, our eggs have a finite shelf life and the odds of having a child over 40 years old are shockingly slim.

According to the Southern California Center for Reproductive Medicine , a woman in her 20s has a 20-25% chance of conceiving naturally per menstrual cycle. In her early 30s, the chance of pregnancy is 15% per cycle. After 35, the odds of pregnancy without medical intervention are at 10%. After 40, that number falls to 5%, and women over 45 have a 1% chance of conception.

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The number of childless women in the United States today is growing. According to a Pew study conducted in 2008, about 18% of women in the United States don't have children by the end of their childbearing years. In 2008, there were 1.9 million childless women between 40 and 44, compared with 580,000 in 1976.

From the Pew report: "Among older women, ages 40-44, there are equal numbers of women who are childless by choice and those who would like children but cannot have them, according to an analysis of data from the National Survey of Family Growth."

Perhaps one of the greatest myths today is the ability of science to step in and make babies for women at virtually any age. Selvaratnam says that we see the success stories, but rarely hear about the huge numbers of failed attempts. A 2009 report on Assisted Reproductive Technologies, or ARTs, by the Centers for Disease Control and Prevention found that the single most important factor affecting the chances of a successful pregnancy through ARTs is a woman's age. Selvaratnam reports that at age 40, the chance is 18.7%; at 42, it's 10%; at 44, it's only 2.9%.

"We are the guinea pig generation for testing the limits of our fertility, or our chances of having a child. The shock and the lack of preparation when you're not prepared and the pressure women feel in general about our reproductive selves adds to the shame women feel when they can't get pregnant," Selvaratnam said.

She also argues that feminism may have misled Gen X women by avoiding the topic of motherhood and biology. The trend of delaying motherhood was meant to empower women, but ironically it may have boomeranged, leaving scores of women infertile and desperate to have a baby. Selvaratnam believes that we need to reset the conversation and reconcile motherhood with also being an educated, independent, successful woman.

Like birth control, Selvaratnam suggests that information be promoted about fertility and the realities of delaying motherhood. She suggests that every young woman be shown a chart of her overall fertility so she understands when her eggs are best and when the number will start declining. She thinks that with the information, women can be more strategic about trying to get pregnant or at least not be blindsided if they have difficulties because they waited.

The attrition rate of our eggs is startling. Selvaratnam reports that the number of eggs at a girl's first menstrual cycle is 300,000 to 400,000. By age 30, we're down to between 39,000 to 52,000, which is about 13% of the eggs we had at puberty. By age 40, we have only 3% of our initial cache of eggs -- about 9,000 to 12,000 eggs -- and many of these eggs will not be viable.

Ironically, in our uber-sharing age, infertility still remains shrouded in silence. Selvaratnam wants to de-stigmatize miscarriage and infertility and get people connected and talking.

"When women have miscarriages or infertility we feel like failures. I want people to realize how common these issues are. When you see the statistics, it becomes clear you are not alone," Selvaratnam said. "You look at celebs and think 'What's wrong with me?' when it seems to work out for all of these other people. But the truth is, for most people, it doesn't work out."

Selvaratnam is also hoping that her book will be a policy changer. She's advocating for better health insurance to cover infertility treatments as well as better public education for women. Changing the paradigm for women in the workplace, increasing work-life flexibility and creating more affordable child care, she believes, is also intricately linked with supporting women so they can become mothers. Taking some time off from your career, or easily coming back to your job is a fundamental issue for easing the path for women to have a baby in their late 20s or early 30s -- the optimal time for fertility, but often a terrible time to interrupt careers.

"We place so much pressure on women in regard to ... their reproductive selves and on their careers. So many women are suffering," Selvaratnam said. "We need to find ways to advocate, small and big. Instead of judging each other,we should be supporting each other. I want people to look at my story and see and see how they can prevent it from happening to them."