In the first incident in 2013 the couple's first baby, Rahul, ended up in the intensive care ward at a hospital in south-eastern India's Viluppuram District, in the Tamil Nadu State, after neighbours had heard him screaming, and rushed into the house from outside to discover the child on fire in his cot.
His mother, who was working in the fields, took him to hospital and since then he has caught fire another three times, she claimed.
Does spontaneous human combustion really exist?
One of the first serious accounts of it appeared in the august journal Philosophical Transactions Of The Royal Society in 1745, which recorded how a 62-year-old Italian countess had gone to bed one night feeling 'dull and heavy'. The next morning, all that was found in her bedroom was a pile of ash and her legs.
Many other cases followed, and by 1806, one scientist thought he had the answer. In An Essay On The Combustion Of Humans, Pierre Lair suggested that the problem was the demon drink, and he subtitled his article, Products Of The Abuse Of Spirituous Liquors.
The explanation that alcohol was to blame quickly caught on, especially among moralists who were against the hard stuff. In 1832, a popular Victorian magazine claimed all those who suddenly burst into flames were 'habitually drunken'.
The notion was so widespread that when Charles Dickens included an episode of spontaneous human combustion in his 1852 novel Bleak House, the victim — the villainous Mr Krook — was said to be 'continual in liquor'.
British research biologist Brian J. Ford argued in two articles, one of which appeared in the New Scientist, that spontaneous human combustion may be caused by a chemical called acetone that is produced naturally in the body, the chemical often used as a solvent in nail-varnish removers.
In healthy humans, acetone is normally disposed of through urine, but when people suffer from certain illnesses, acetone levels can build up in the body, and can even be smelled on the breath.
On the website Mumsnet, one poster wrote that her young daughter had 'acetone breath', and that 'apparently children have higher than normal acetone levels'.
Professor Ford has noted that many of the people who have combusted spontaneously were unwell at the time, and as a result, may have developed a condition called ketosis, in which acetone in the body increases.
Ketosis can have a range of causes, including alcoholism, diabetes, a high-fat diet, and even, in babies, teething.
Furthermore, acetone infuses itself well into human fat. And it is also extremely flammable.
Unable to find a human volunteer to test his theory that a build-up of acetone causes spontaneous human combustion, Professor Ford made a model from pieces of pork - the animal flesh that most closely approximates ours.
The 'pork puppet' was marinated in acetone, dressed in clothes, and placed in a chair. Professor Ford then held up a gas lighter, and the result was dramatic. The 'body' burst into a fireball, and in under an hour, it had been completely consumed by flames.
In fact, the acetone was so volatile, that even just a static spark from synthetic fabrics could have caused the conflagration.
All that was left - as is so often the case with spontaneous human combustion - were the legs, which Professor Ford suggests remain unburned because there is not enough fat in that part of the body to store the flammable acetone.