Doctors have called time on big families. A recent editorial in the British Medical Journal talked of discouraging patients, on environmental grounds, from having too many children. The more people, the bigger the drain on global resources.

The editorial advised GPs not to put pressure on patients, but “by providing information on the population and the environment, and appropriate contraception for everyone...doctors should help to bring family size into the arena of environmental ethics, analogous to avoiding patio heaters and high-carbon cars”.

Watching her full complement of two tots kicking their organic pig's bladder around on the hand-weeded lawn, a mother is presumably expected to tell their father: “I'd love to have another baby, darling, but think of its carbon footprint.” Hmm, shall we have a patio heater, a high-carbon car or another baby? Maybe we could have another baby and offset it by composting or low-energy bulbs? The nanny state rocks on. Or not. After all, no baby, no nanny. A cradle-to-grave health system without the cradle, as the doctor hands you a prescription with the words “Please consider the environment before having sex with your spouse”.

Too late for me, doctor. I have three children. Any parent with more than two children will tell you the same - screw the planet. Forget the damage to the environment, focus instead on the damage the cherubs are doing to your sanity. I love them all but I cannot pretend that my life isn't chaos. Look what happens when you keep to one child per family - you save on the 400million children who might otherwise have been born, your economy takes on the world and your sportsmen clean up at the Olympics. (Although the fact that you need a talented child who sings like an angel and another one who looks like one may give the Chinese authorities pause for thought in future.)

Perhaps the doctors are right to try to intervene. Perhaps parents should think more deeply about the consequences of having children. Instead, the binge parent thinks: “I want a baby that looks like you. I want a baby that looks like me. Well, we could fit a little one in that looks like your father. And now, I want one that looks like Beyoncé.” This approach can mean that you wake up 18 children later with 42 sliced white loaves on your weekly shopping list and “feckless f***ers” painted on your front door by irate neighbours. Even worse, in future those neighbours are likely to be urged on by ecoactivist doctors from the local health centre.

But perhaps binge parents already think about the consequences - just not the environmental ones. I think: “If I have a large number of children, one of them may still love me when he grows up.” If you are very lucky as a mother, you may get a boy-man who rings you in the middle of his Olympic diving event or, I don't know, sets up a webcam on his honeymoon night to share the moment with you.

The idea of having a large family so that they can be an emotional crutch in your dotage is distasteful, though, as is considering them an alternative pension plan. Then again, they owe you, if you look at the figures compiled by LV (the insurance and investment group formerly known as Liverpool Victoria). On average a child costs you £186,032 from birth to his or her 21st birthday (that is to say, £8,859 a year). Raising three children, then, costs more than half a million pounds. That explains the overdraft.

This in austerity Britain, when we are shopping in economy superstores and making our own clothes. When our motorways are full of debt-laden, fuel-conscious drivers travelling at a constant 55mph on the motorway, their right legs at risk of deep-vein thrombosis. And a solution to their financial problems is available in one easy, rubber-sheathed thrust: no more children.

But the disadvantages of large families are more than financial. More importantly, they include a skull-crushing sense of imminent crisis. School holidays only exacerbate this. Suddenly parents are juggling complicated schedules of office rosters, paid childcare, granny and grandad time and “activity weeks” involving circus skills. One child, maybe two, can be palmed off if you have a particularly understanding support system and do it early enough in the summer holidays. Hand over three feral children from mid-August onwards and granny is likely to write you and her only son out of the will and post back the children's body parts in clearly-labelled Jiffy bags.

Even when you take responsibility for your children and go on holiday, a large family such as mine has difficulties in travelling. Three children and upwards, you become not so much paying guests as a Hydra-headed “problem to be dealt with”. Our recent holiday highlights included a stiff-jawed Cumbrian hotel restaurant manager informing us the children's menu finished at seven sharp and warning us not to allow our children to “run round the dining room” if we came down at 7.01pm. They also included a smug Eastern European receptionist shrugging off the confirmed booking of interconnecting rooms and forbidding us to put the seven-year-old, five-year-old and two-year-old in a bedroom on their own across the corridor, which obviously, in these post-Madeleine McCann days, is just what we were planning.

Parents like me can only shake their heads in sympathy at the story of the couple with four children and 18 pieces of luggage who managed to leave a four-year-old behind in the airport shop while they boarded the flight from Tel Aviv to Paris (tell me what Freud would have said about that one). While everyone else seems keen to condemn you, parents with more than two children are among the least judgmental people in the world they are so busy destroying - they know that tomorrow, that screaming or forgotten child might be theirs.

Judith O'Reilly is the author of Wife in the North (Penguin, £7.99). www.wifeinthenorth.com

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