Spinning stories about Santa risks undermining a child's trust and is morally suspect, according to two experts.
Psychologist Professor Christopher Boyle and social scientist Dr Kathy McKay also condemn the idea of a "terrifying" North Pole intelligence agency which judges children to be nice or naughty.
Writing in the journal The Lancet Psychiatry, they argue: "If they (parents) are capable of lying about something so special and magical, can they be relied upon to continue as the guardians of wisdom and truth?"
In addition they suggest parents may not be motivated by thoughts of their children but a selfish desire to re-live their own childhood.
Defending the claims, Prof Boyle, from the University of Exeter, said: "The morality of making children believe in such myths has to be questioned.
"All children will eventually find out they've been consistently lied to for years, and this might make them wonder what other lies they've been told.
"Whether it's right to make children believe in Father Christmas is an interesting question, and it's also interesting to ask whether lying in this way will affect children in ways that have not been considered."
Dr McKay, from the University of New England in Australia, said there was clear evidence from the world of make-believe in movies and TV that adults looked for a chance to be children again.
"The persistence of fandom in stories like Harry Potter, Star Wars and Doctor Who well into adulthood demonstrates this desire to briefly re-enter childhood," she said.
While many like to moan that the cost of Christmas seems to go up every year, the truth may be exactly the opposite. According to an index that tracks seasonal food, the price of Christmas dinner is now at its lowest since it started in 2009. A separate calculation suggests that Christmas trees, too, are getting cheaper, costing just a quarter of what they did back in 1975. One reason for falling prices may be the arrival of low-cost supermarkets. However, the increasing cost of importing food may mean that Christmas 2016 will mark the low point for prices. The Christmas dinner index - compiled by Good Housekeeping magazine - suggests that the 11 ingredients necessary are now 10.8% cheaper than they were in 2009. Buying everything from the turkey to Christmas pudding is likely to cost £2.48 a head this year, if you bought each in the cheapest supermarket. In 2009, the equivalent cost was £2.78, according to the index. 'Think carefully' Separate research that goes back as far as 1968 comes to a similar conclusion. The figures suggest that Christmas dinner last year was the cheapest on record, at £37.37 for a family of four. Back in 1975 the same dinner cost nearly £55, after adjusting for inflation, according to the home interiors firm Hillarys, which compiled the research. Last year a Christmas tree cost an average of £24.99, compared with £208 in 1975, it says. The reduction in the average cost of this year's Christmas dinner is largely down to the German supermarkets Aldi and Lidl. Buying all 11 ingredients to feed eight people will cost as little as £22 at Aldi, the Christmas dinner index shows. The same ingredients would cost nearly £50 at Marks and Spencer. "While five of the supermarkets have cheaper baskets this year, it's mainly thanks to the big decrease in the cost of these groceries at Aldi and Lidl that the overall basket is significantly cheaper," said Caroline Bloor, the consumer director of Good Housekeeping. "So think carefully where you shop or you could end up paying twice as much." Cost of Christmas dinner 2016 (for 8 people) Supermarket Cost of ingredients Aldi £22.03 Lidl £24.57 Iceland £24.81 Tesco £28.08 Asda £29.68 Morrisons £31.12 Co-op £31.26 Sainsbury's £35.40 Waitrose £40.02 M&S £49.90 source: Good Housekeeping Christmas dinner index includes: turkey, vegetables, Christmas pudding, mince pies, brandy butter