Mothers who want to take their babies to the Olympic Games may have a case for sex discrimination if they are prevented from doing so, it has emerged.
Rules set by 2012 organisers say every baby - including those who were not conceived when their parents bought seats - must have their own ticket or they will be excluded from the Games.
Expectant mothers have described the policy as "discriminatory", especially to those new mothers who will be breastfeeding.
Most tickets went on sale last April - 15 months before the Games.
Expectant parents have been told they can try to buy an extra ticket for their chosen event, although there are concerns that none will be available for popular events, forcing mothers to stay at home.
Under the current rules, expectant parents who are successful in getting an extra ticket for their baby will be able to hold the infant in their laps.
They will need to show the baby has a ticket for somewhere in the venue, even if they do not plan to use the seat.
Last night a spokesman for London 2012 said organisers would look again at the policy.
He said: "We want families and young people to come and enjoy the Games, which is why we created Pay Your Age tickets at a third of sessions.
"Of course, we understand that some new mums may want to take their babies to events they have tickets to and we will look at what we can do when the remaining tickets go on sale in April."
But this information did not include a policy on babies conceived after their parents bought tickets.
The issue has attracted fury on the Mumsnet website, with parents saying they are being forced to pay full price for babies not yet born. Others said they could miss out altogether.
Ticketholder Rosalind Ereira told the Guardian she has contacted the Equality and Human Rights Commission (EHRC), which said she may have a case for "indirect sex discrimination", as the policy is more likely to affect women than men.
In a statement to the Guardian, the EHRC said: "A business must not do something which has a worse impact on you and on other people who share a particular protected characteristic, such as gender, than it has on people who do not share that characteristic.
"Unless the business can show that what they have done is objectively justified, this will be what is called indirect discrimination.
"It could be argued that women are more likely to have child caring responsibilities and thus this policy might have more of an impact for women, but as stated above the business might be able to justify this potential discrimination."
Justine Roberts, co-founder and chief executive of Mumsnet said yesterday: "It's an ill-thought-out policy and I think the feeling on Mumsnet is that it's discriminatory.
"If you have got a very young baby, you can't leave it behind if you're breastfeeding, you have got to take it with you."
She said expectant parents had been left with a situation where they had to pay full price for another ticket, if they could get one, which would make it impossible for some new mothers to go.
"It shows a lack of understanding in many ways," she said.
"What were you supposed to do? Buy a ticket for a potentially unborn or unconceived child?"
The National Indoor Arena (NIA) in Birmingham, which hosts a range of international sporting events, said its policy for those is that babies do not need a ticket to attend.
A spokesman said: "We don't have a strict age policy in place. However, we say that generally before a child is walking, we are happy for them to be admitted without a ticket.
"Once a child is old enough to be walking and requires their own seat, it is then necessary for them to be ticketed."
The NIA said venue policy can be subject to change on a show-by-show basis.
At Lord's cricket matches, babies and toddlers under three go in for free.
Wimbledon does not recommend babies are taken. Children under five are allowed in without a ticket - but may not enter Centre Court or the other show courts.
At Wembley Stadium, restrictions vary on an event-by-event basis. For those events which do allow children under 16, all spectators must have a ticket.
At Twickenham Stadium, children under two do not require a ticket but must be securely strapped to an adult sitting in the lower tier.Suggest a correction