The husband is understood to be on a life support machine at the Royal Free Hospital, Hampstead, north London, following a road accident 10 days ago. Neither partner has been named.
Last week doctors and lawyers called for a review of the law which forbids freezing and storing human sperm without consent. They said it was never intended to apply in such circumstances.
Because the injured man is in a coma and unable to give his consent to storing the sperm, hospital authorities say they are unable to comply with the woman's wishes under the Human Fertilisation and Embryology Act, 1990. The Act expressly forbids sperm storage without the donor's consent.
Last week the hospital declined to provide any information about the case. It said the woman, who was initially thought to be considering legal action, had accepted the ruling.
Embryologists and fertility specialists criticised the law as too prescriptive.
'This situation should be brought to the attention of the legislators and an amendment should be made,' said Professor Ian Craft, director of the London Gynaecology and Fertility Centre.
'The law should be more flexible and take this kind of situation into account. We do not know the full circumstances, but what if the woman has been infertile or on the pill for 15 years? It is tragic.'
Dr Virginia Bolton, senior embryologist at the assisted conception unit at King's College Hospital, London, said: 'I have never heard of a situation like this before. What a tragedy]
'We see couples regularly where the husband is seriously ill and has his sperm stored for future use, and there is nothing wrong in that.
'Why should this be any different because the man is on a life support machine?'
Dr Wendy Savage, professor of obstetrics and gynaecology at the Royal London Hospital, said: 'This looks like yet another drafting error in the legislation. It shows that with the increasing complexity of society we are getting laws that are far too complicated and not properly thought through.'
The Act has already been amended once following complaints from doctors and pressure groups over restrictions on the use of patients' notes.
Sperm is routinely collected for use in sperm banks or for private storage. Under the Act, donors have to fill out a detailed form, and there is provision for them to state what they want to happen to their sperm after death.
The law was introduced to regulate sperm banks and ensure confidentiality, and to allow babies born as a result of donor insemination to discover the names of their true fathers.
A spokesman for the Department of Health said that it would welcome a clarification of the law.