Children born with the help of donated sperm or eggs should have the fact recorded on their birth certificates, a group of MPs and peers has suggested.
Fertility technology has advanced in recent years
They say the measure would give parents an incentive to discuss the topic before children found out themselves.
The cross-party group made the recommendation in a review of the draft Human Tissue and Embryos Bill.
The committee also called for a number of significant changes to the proposed overhaul of fertility laws.
The Bill is expected to be included in the Queen's Speech in November.
But the Joint Committee report raises serious questions about whether it will continue in its current form after all 18 members agreed that the draft bill was flawed.
The committee was set up to scrutinise the proposals before their passage through Parliament on the way to becoming law.
At present, a child conceived using donated sperm or eggs can grow up not knowing this fact, if his or her parents choose not to reveal it. They only gain the right to check on their parentage at the age of 18.
The committee said that this amounted to the state being party to a "lie" and called on ministers to give consideration to compelling parents to include the detail on the birth certificate.
But Liberal Democrat science spokesman Dr Evan Harris said the recommendation was a "bizarre and intrusive solution to a problem that has never been demonstrated to exist."
He said: "There is no proper evidence that children or adults suffer from not knowing who their 'real fathers' are, whether from IVF or from infidelity."
Dr Vivienne Nathanson, head of science at the British Medical Association, said it was important that parents were helped to give their children information about the way they were conceived.
But she said: "Putting it on the birth certificate means that the child may find out unexpectedly far too young."
The committee also said the proposal at the core of the draft bill, combining two existing regulatory authorities - the Human Fertilisation and Embryology Authority (HFEA) and the Human Tissue Authority (HTA) - into one "truncated" body should be abandoned.
Use of donated sperm or eggs to be recorded on birth certificate
Permit embryo selection to produce tissue to treat children with serious, but not life-threatening diseases
Relaxation of ban on research using hybrid embryos
Scrap plan to merge Human Fertilisation and Embryology Authority and the Human Tissue Authority
Reconsider plan to drop father-figure clause when considering offering IVF
The government's proposed Regulatory Authority for Tissue and Embryology (RATE) would govern both IVF clinics and research involving fertility and embryos, and the storage, use and disposal of human bodies, organs and tissues.
The committee said the benefits would be small, and scrapping the well-regarded HFEA could undermine public trust in the way fertility services were regulated.
Committee chairman Phil Willis said: "There is a desperate need to make sure that the public believe that the regulator is acting on their behalf, not simply on the behalf of science."
The committee also took issue with the proposal to remove the current requirement for IVF clinics to take into account the need for a father.
They said it was right that lesbian couples should be considered for IVF, but said removing the father clause could encourage clinics to downgrade the importance of a two parent family.
But the committee said the proposals on so-called saviour siblings, where embryos are selected to produce IVF babies whose tissue can be used to treat an existing sick brother or sister, did not go far enough.
They said use of the technique should be widened to include not only life-threatening diseases, but also serious disease which had an on-going impact on quality of life.
The committee also questioned proposed limits on research using hybrid human-animal embryos.
Mr Willis said progress was being stymied by a shortage of donor human embryos or eggs.
He said these were "significant changes" that would totally alter the architecture of the current draft bill.
"I hope the government gives our recommendations their full consideration. I don't think the bill in its present form would gain the support of MPs."
The report was broadly welcomed by scientists and doctors.
Professor Robin Lovell-Badge, of the National Institute for Medical Research, said the committee had worked very hard to "solve all the issues" and he was reasonably content with the findings.
"I fully support their rejection of the merger of the HFEA and HTA to form RATE - this would create a chimeric body far more troubling than any I can imagine."
Health Minister Dawn Primarolo said: "We are grateful for the report by the pre-legislative scrutiny committee, which we will study with interest, and respond to in due course.
"The current law has served us well, but needs revision. Technology has changed and so have attitudes."