Two women have gone to the High Court to try to win the right to use frozen embryos against the will of their former partners.
Lorraine Hadley (left) and Natallie Evans at a previous hearing
Natallie Evans and Lorraine Hadley are challenging a law which says both parties must consent to the storage and use of the embryos.
They say the frozen embryos represent their only chance of having a child, and denying them the chance to use them infringes their human rights.
Ms Evans, 30, of Trowbridge, Wiltshire, had six embryos frozen before undergoing cancer treatment.
She had to have her ovaries removed after it was discovered they were pre-cancerous.
I am here today to ask the court to let me finish what I have already started
Ms Hadley, 37, from Baswich, Staffordshire, is bringing a similar action against her ex-husband.
She has a 17-year-old daughter from a previous relationship, but suffers from fertility problems because of a medical condition.
But her former husband, Wayne, refused to allow the embryos being used because he did not want a child to be born so many years after the end of their marriage.
Robin Tolson QC, opening the case told Mr Justice Wall there had been 70,000 babies born through IVF in this country alone.
Howard Johnston is Natallie Evans' ex-partner
"In human terms the question is whether you are going to allow either or both the chance to add to that number."
In court, Ms Evans said she would have pursued a different form of treatment if she had known her former husband would one day withdraw his consent for use of the embryos.
She added: "My embryos are my last
chance of having a child of my own. I would do anything to have one."
Ms Evans said her husband had initially promised he would not stop her using the embryos.
But a legal contract to that effect was never drawn up, and she later received a letter from the clinic where the embryos were
stored which said her former husband wanted them destroyed.
James Grigg, solicitor for Howard Johnston, said: "Mr Johnston has a great deal of sympathy for Ms Evans in these difficult circumstances.
"He very much hopes that she will eventually be able to understand his decision.
"Mr Johnston also hopes that Ms Evans's wish for children can be satisfied in some other way, perhaps within a new relationship and by the use of a donor egg."
Ms Hadley added: "I am here today to ask the court to let me finish what I have already started. I have two embryos in storage and want the opportunity to
use them and I don't want them destroyed."
The 1990 Human Fertilisation and Embryology Act says embryos cannot be implanted in a woman unless both partners involved in their creation consent to the procedure.
But the women's lawyers argue that the Act breaches the women's human rights under European law.
They say the women are being discriminated against because they are now infertile and having to undergo IVF treatment.
The pair say that once the embryos have been created and stored it is too late
for consent to be withdrawn and that to destroy them is a breach of their human
Muiris Lyons, the women's solicitor, said: "The case raises important legal, moral and ethical issues as to the rights of an embryo, its status and position in law, and the competing interests of a woman desperate to become a mother and a man who has no wish to become a father."
He added: "The judge has got to balance a woman's right to become a mother in these circumstances, with a potential father's right not to become a father."
Mr Lyons said that if the court found in favour of the women, the Human Fertilisation and Embryology Authority would have to undertake a review of the existing regulations governing IVF.
The case, which is expected to last up to six days, was adjourned until Tuesday.