LAST weekend I went to a party given by a friend who has just had a baby. Half the other guests had just had babies too, and infants were everywhere.

I sat between two women who were earnestly locked in discussion about their return to work. One was self-employed and had taken no maternity leave while the other was halfway through a year off and planning to return part-time.

As I listened to them, I remembered that mixture of camaraderie, competitiveness, anxiety and exhaustion, and thought how little had changed in the 20 years since I had my first child. These questions of how to divide time between a baby and a job are being asked with just the same urgency and confusion as they were then.

Despite the fact that we have two extra decades of data, we aren't any closer to an answer. When a heavily pregnant Marissa Mayer recently landed the job as CEO of Yahoo, the only sensible response was to shrug. After all, she's not the world's first successful pregnant woman. But no one did shrug: instead, more than 4000 newspaper articles were written, variously judging her to be a heroine, a bad mother, a great role model and no role model at all.

In a way, it is boring and pointless to be having these discussions all over again. Yet I understand why we haven't found satisfactory answers: it's because there aren't any. There is no best length of maternity leave. There is no best way of combining motherhood and jobs. Above all, there is no balance. Instead, it's a continuous, fluid game of survival, the rules of which are different for everyone.

To realise this should mean that we can stop talking about it. But the reason we can't do that is that it feels too important. My decision to spend a third of my life writing articles such as this one, rather than telling the children to get off Facebook, feels like the most difficult one I've ever made. Yet unlike most other big decisions - where you can usually work out at least with hindsight if you got it right - with this you never know. There is no control test.

In fact there is no such thing as right: there are just lots of varieties of wrong. Just the other day, one of my children phoned me at work to say he was going to a pop festival and when I got home he'd gone to some unknown destination with almost no money, no food and no sunscreen. That felt vaguely wrong.

This is how it works. It's a process that involves much trial and many errors, and when the errors seem too great, we do an Anne-Marie Slaughter and hope for fewer of them under the new regime. What was remarkable in her case was not that she quit a fancy job in the White House or that she wrote a bonkers article in which she declared that her volte face proved that women couldn't have it all. What was extraordinary was that she had reached her sixth decade without having worked that out before.

Otherwise, and in the absence of any better way of measuring how we are doing, we compulsively engage in something soul-destroying: we compare. We compare ourselves to Slaughter and to Mayer, and when we've tired of comparing ourselves to outliers, we go on internet chat rooms and compare ourselves to people who can't even use capital letters.

But mostly we do what the women at the party were doing and pointlessly compare ourselves to people we know. I get a nasty feeling in my stomach when I hear a friend has sent her children to Florence for the summer on history of art tours but feel a little lift when another declares that her kids are spending their vacation sleeping until noon and spending afternoons on the sofa watching YouTube in the dark.

Both responses are stupid as their children aren't mine. Yet, as a result of such comparisons, I've found something cheering in a grim way.

A friend who quit work decades ago to raise four delightful, funny and cultured children has just been told by her eldest that she's a pathetic cipher who has wasted her life. Funny, that. One of my children told me not so long ago that I was so busy living my own life I had no idea what was going on in theirs.

There is only one certainty in playing this individual game of survival. Whatever you do, there will be angry voices in the media telling you that your answer is wrong. But there is no need to listen to them when there is an angrier adolescent at home telling you just the same thing with even greater conviction.

© 2012 The Financial Times Limited