KEY POINTS:
SYDNEY - You'd think having children would be taxing and expensive enough.
Not so, says an Australian medical expert who is calling for couples to be charged A$5000 ($5700) a head for any "extra" children they have - that's every child after their second.
Professor Barry Walters even thinks parents should incur an annual tax of up to A$800 every year - for life.
But wait, there's a silver lining in that nappy.
Coughing up under the controversial plan could help to save the planet, he writes in the latest Medical Journal of Australia.
The lifelong tax would simply offset the extra offspring's carbon-dioxide emissions, he explains.
What's more, couples who get sterilised would be eligible for carbon credits.
Considering his opinion of baby carbon footprints, it comes as no surprise that the Perth specialist is heavily critical of Australia's A$4000 baby bonus.
Paying new parents extra for every baby fuels more children, more emissions and "greenhouse-unfriendly behaviour".
Instead, it should be replaced with a "baby levy" in the form of a carbon tax in line with the "polluter pays" principle, he wrote.
"Every family choosing to have more than a defined number of children should be charged a carbon tax that would fund the planting of enough trees to offset the carbon cost generated by a new human being," said Walters, an obstetrician at King Edward Memorial Hospital in Perth.
Sustainable Population Australia suggested a maximum of two, he said.
By the same reasoning, contraceptives such as diaphragms and condoms, as well as sterilisation procedures, should attract carbon credits. "As citizens of the world, I believe we deserve no more population concessions than those in India or China."
Professor Garry Egger, director of the New South Wales Centre for Health Promotion and Research, agreed saying former Treasurer Peter Costello's request for three children per family was too single-minded.
"Population remains crucial to all environmental considerations. The debate needs to be reopened as part of a second ecological revolution," he said.
Family groups have rejected the calls, claiming larger families use less energy than smaller ones and therefore should not be penalised.
- AAP