An influential group of MPs is considering whether any medical research suggests the 24-week cut-off point for abortion should be changed.
MPs will hear about medical advances over the past 40 years.
The science and technology committee is examining the impact of termination on the mother's health and whether babies under 24 weeks can survive.
The Pro-Life Alliance wants the upper limit cut to 20 weeks.
But the British Medical Association says the number surviving at 24 weeks is still "extremely small".
According to the Department of Health, there were 193,000 abortions in England and Wales last year. Of that total, 89% were performed in the first 13 weeks of pregnancy.
The Pro-Life Alliance says babies born at 24 weeks now have a much better chance of survival than when the Abortion Act was passed in 1967.
In recent times the debate has been given a more visual impact with the introduction of three dimensional images of foetuses at just 12 weeks showing apparent facial expressions.
During its inquiry, the Commons science and technology committee will hear evidence on what medical advances there have been over the past 40 years.
The issue will also be aired during debate on the Human Tissue and Embryos Bill next month.
Lord Steel, whose private member's bill led to the Abortion Act 1967, said he was "following the lead of the BMA", which believes the limit should remain unchanged.
"We ought to wait for the considered view of the medical profession," he told BBC Radio 4's Today programme.
However, Professor Stuart Campbell, formerly professor of obstetrics and gynaecology at Kings College, London, who pioneered 3D images of foetuses, said he believed the abortion limit should be reduced to 20 weeks.
"Foetuses can survive even at 23 weeks," he told Today. "Even at 22 weeks there's a reasonable survival rate, admittedly many of those babies are handicapped.
"With medical advances, babies born between 20 and 24 weeks can survive."
Cooling off period
Using his scanning techniques, Prof Campbell said he could see quite complex behavioural patterns in foetuses, with facial expressions, such as smiling and crying, plus thumb sucking, eyelids opening and breathing movements.
"I feel pretty appalled at the idea that we abort normal babies and most of them are born alive and most of them are allowed to die," said the professor, who used to carry out abortions at 20 weeks.
Julia Millington, political director of the Pro-Life Alliance, said advances in science meant "our understanding of foetal viability has changed".
The Pro-Life Alliance also wants a "cooling-off" period, because it believes some women are having an abortion without the time to think it through.
But Dr Tony Calland, chairman of the BMA's medical ethics committee, said that after debating the issue, his organisation felt that despite "very considerable" scientific advances, the time limit should stay the same.
He also wanted to remove the requirement for a woman wanting an abortion in the first three months to gain permission from two different doctors.
"As long as they have had all the risks and benefits explained to them, discussed with them so they have an appropriate amount of information to make a legitimate decision, we feel it is up to them to decide what is best for them," he said.
Lib Dem MP Evan Harris, a former hospital doctor who sits on the Commons committee, believes there is a need to update the law.
He said benefits could include, for instance, women being allowed to have a medical abortion - in which they take a pill at up to nine weeks' pregnancy - completed at home rather than in hospital.
When the Abortion Act was first passed the normal time limit for termination was 28 weeks, but this was lowered to 24 in 1990.