Babies will be banned from this year's Olympic Games unless they have their own ticket - even if they were not conceived when their parents bought seats.
The 2012 organisers have said every child, including small babies carried in their parents' arms, must have their own ticket or they will be excluded from the Games.
The issue has attracted fury on the Mumsnet website in the last few weeks, with parents saying they are being forced to pay full price for babies not yet born.
Some are doubting whether extra tickets will be available for the popular events they are attending.
One woman described it as the "biggest rip-off in the history of London" while others wondered what to do with babies they will be breastfeeding.
Another said: "The whole thing is ridiculous, there are people who bought tickets before their babies were even conceived - how are they supposed to know to buy a ticket for a child that doesn't exist yet?
"There should be more complaining about this policy. It's nuts."
A press spokesman admitted the Olympics helpline had received calls from pregnant women and expectant fathers whose babies will just be a few weeks old when the Games commence.
They have been told they can try and buy an extra ticket for their chosen event, otherwise the infant will be prevented from entering the venue.