Is the Biological Clock a Real Thing?

Women at a certain age supposedly hear a loud ticking sound: The biological clock that tells them to have children and how much time they have left to do so.

But is it a real thing? It's a complicated question, and the answer depends on what you're trying to learn and whom you ask.

It's also a loaded issue, fraught with opinions, emotion and unwanted advice.

The facts may surprise you.

Popular culture is rife with stereotypes of the woman whose career ascends while her personal life unravels as that biological clock ticks away.

Many women swear that they don't want children, only to find themselves suddenly desperate to do so.

Others are bombarded with warnings that they're waiting too long, with the biological clock dictating that fertility craters in women after age 35.

It might be helpful to start with a few facts.

Does biology activate an urge in women to have children?

Or is it just a pervasive myth fueled by bad science?

"Biological clock" has multiple meanings.

Until the last few decades, the phrase primarily was used to refer to the body's natural sleeping and waking rhythms.

Most scientists in the field of sleep research still use it that way.

The usage of "biological clock" to mean "an obsession with having children" is a recent invention, coined by a newspaper columnist.

The 1970s saw a radical shift in what had been the American paradigm of the traditional family.

Women were entering or re-entering the workforce in skyrocketing numbers, and many were putting off or avoiding having children to do so.

That lead Washington Post columnist Richard Cohen to pen a column on March 16, 1978, called, "The Clock Is Ticking for the Career Woman," which outlined the new struggle for women who want to "have it all."

Cohen wasn't writing as a scientist or as a researcher unveiling a survey, but as a columnist offering his opinion.

The Origin of the "Biological Clock"

There's little compelling evidence that a hormonal urge to have children exists.

While the term wasn't popularized by scientists, the idea of a woman's fertility as a clock that gets louder has been studied extensively.

And there is virtually no evidence that a biological urge kicks in for a woman of a certain age.

At the same time, many studies have found a high number of women with no interest in children whatsoever – no matter their age.

But "Baby Fever" does exist.

There is ample evidence that both men and women can have a sudden and all-consuming drive to have a baby.

A study published in 2011 by Kansas State researchers Sandra and Gary Brase followed hundreds of subjects for a decade and found a real correlation between encounters with children and an increased or decreased desire for them. And, shockingly, what they call "baby fever" in men tends to peak in the 40s – the same time the supposed biological clock is screaming loudest in women.

There's evidence that men reach an age where their fertility begins to fall off.

There is a time where women can't conceive children anymore and a period of time before that when the risks of doing so rise sharply.

New research has also shown that men have a similar time when it becomes harder and more risky to father children. Despite cultural images of men in their 70s fathering kids, we now know that the amount and quality of semen decreases, the risk of miscarriage is higher, and children born to older fathers tend to have more genetic abnormalities.

It seems clear that the stereotypical biological clock simply doesn't exist in the way that most depictions of it suggest.

The sudden desire for a baby isn't a physical or hormonal change, but an emotional state that some people feel and others don't. It's definitely not present in every woman's life and can be screamingly loud for men.

In the end, having children remains a decision that only a woman and her partner can make, and it should be made without cultural factors, expectations, or bad science guiding them.