"The chances of falling pregnant in your mid-40s is roughly the same as a male underwear model reading a chick-lit novel" ... Kasey Edwards

The baby myth ... Why are we still invested in the collective fantasy that women can pop out a baby whenever they choose?

I have seven years, eight months, 17 days, 11 hours and 46 minutes until I'm barren. At least that's what my Wonder Clock tells me.

The Wonder Clock is an iPhone app which, for the bargain price of $1.99, tells you when your biological clock will expire.

I sat in an IVF waiting room full of women who confidently 'waited until next year', and the only thing they left with was a broken heart  

According to the app's developer, Mira Kaddoura, the clock "empowers women and helps them face their fears about fertility".

There's just one slight problem - it's complete rubbish.

I was diagnosed as infertile four years ago, at age 32 - making this calculation incorrect, in my case, by at least 11 years.

Fortunately, I received my diagnosis while IVF was still viable. If I'd waited a year longer, I would most likely have been unable to conceive.

Admittedly, my case isn't the norm - although it's not uncommon - and the app comes with the disclaimer that it's not a medical diagnosis and works off averages.

But even accepting the averages, the Wonder Clock is still way off. In seven years and eight months, I'll be 44. Most women's biological clocks expire long before their mid-forties.

Despite what we see in Hollywood movies and women's magazines, the chances of falling pregnant in your mid-40s is roughly the same as a male underwear model reading a chick-lit book.

According to the Southern California Centre for Reproductive Medicine, at 35 women have only a 10 percent chance of conceiving a month. At 40, that's dropped to a 5 percent chance of conceiving naturally, and no more than a 10 percent chance of conceiving with IVF. Even if you're lucky enough to conceive after 40, your risk of miscarriage skyrockets by 33 per cent.

These statistics aren't new and aren't a secret: Google it and you'll find pages and pages of research from credible sources. Why, then, are we still invested in the collective fantasy that women can pop out a baby whenever they choose?

When I suggested to my clucky 38-year-old friend that she investigate freezing some embryos, just in case, she replied, ''I don't think I need to worry about that just yet.'' Another friend, who's 42, tells me she and her partner will start trying next year.

I sat in an IVF waiting room full of women who confidently "waited until next year", and the only thing they left with was a broken heart and an enormous debt. If I'd not been lucky enough to receive the tough love, now-or-never speech from a gynaecologist, that could have been me.

I'm not trivialising the baby decision. Finding a partner, getting your finances in order, and sacrificing your career and independence isn't to be taken lightly. But kidding ourselves that we're not that old and we still have plenty of time, when the evidence suggests otherwise, isn't the solution.

The Wonder Clock is another slice of false hope along with other fertility myths served up by well-meaning friends and the media. If you wait too long, you risk losing more than $1.99.

Kasey Edwards is the author of Thirty Something and The Clock is Ticking: What Happens When You Can No Longer Ignore The Baby Question (Random House).