The government is looking into calls to lift a ban on creating human or human-animal "hybrid" embryos from dying children to aid key research.
Some inherited diseases mean children spend much of their short lives in hospital
The current Human Fertilisation and Embryology Bill would not allow the procedure to take place unless the child was competent to give consent.
But critics argue many of these children die before this might happen.
They say the embryos could be crucial to understanding how these diseases work, and thus pave the way for cures.
They also believe the embryos created through Somatic Cell Nuclear Transfer (SCNT), using skin cells from the sick child, may prove the most effective way to test potential therapies.
Spinal Muscular Atrophy
An umbrella group for patients with inheritable conditions, the Genetic Interest Group, Great Ormond Street Hospital for Children NHS Trust, and the UCL Institute of Child Health, have written to health minister Lord Darzi pressing for an amendment.
"The Bill, as it stands, imposes a barrier to one of the most potent tools for research into the most severe childhood diseases," the directors of the three bodies wrote.
They added that in all other matters regarding the health of a child, consent lay with the parents or guardian.
These "may for example include consent to high-risk surgery on behalf of their child and to clinical trials, which involve experimental interventions. SCNT by comparison is a very low risk procedure."
Can't say no
The House of Lords is due this week to finish its discussion of the bill, which is designed to reflect both changing public attitudes and scientific advance. It is due to enter the Commons later this Spring.
Objections have been raised in the Lords to the proposal, notably by Lord Alton, who argued that a non-consenting child might feel "considerable antagonism" that their cells were taken and potentially used to create inter-species "hybrid" embryos.
"Whatever the benefits that may be cited, where is the principle of autonomy?" he asked.
Those behind the amendment argue that one of the key problems is that those who suffer from serious, inherited childhood diseases do not live to an age where they are capable of giving consent.
Diseases cited include Tay Sachs, a neurological disease which kills the child by the age of six, Spinal Muscular Atrophy, which can claim infants as young as 12 months, while the brains of children with Lissencephaly do not normally develop beyond six months.
A spokesperson for the Department of Health said ministers were fully aware of the difficulties posed by the bill in its current form.
"In relation to children, the government believes that some very strong and persuasive arguments have been put forward for cases where, perhaps because the child is suffering from a terminal illness at a very early age, the current consent requirements in the Bill are not appropriate and should be revised.
"We are currently examining this issue carefully."
One of the problems, the spokesperson added, was that the issue surrounding consent did not just relate to children, but also to mentally incapacitated adults, meaning that "more detailed consideration" was still required.