The gift of life is the most precious gift of all. Yet the majority of people who have it in their power to make that gift don't bother.
We are talking about a donation of healthy sperm or eggs which can give infertile couples the chance to have a desperately wanted baby.
A new study by De Montfort University has found that many UK couples are forced to seek fertility treatment abroad, mainly because of a lack of egg and sperm donors in this country.
The average wait in the UK for an egg donor is two years, and for donated sperm it can be up to a year.
More than 500 sperm donors are needed annually in the UK but last year there were only 384. Similarly, more than 1,200 egg donors are needed annually but last year there were just 707.
Clearly, demand for egg and sperm donors far outstrips supply, and Pip Morris, donor recruitment manager at the National Gamete Donation Trust (NGDT), which raises awareness of the need for more donors, stresses: "We've always had a shortage of donors in this country.
"We believe it's purely down to the fact that people don't realise they can help others in this way."
Former Atomic Kitten singer Liz McClarnon, who has championed egg and sperm donation since an ectopic pregnancy scare last year, agrees.
She believes the notion of egg and sperm donation is still "very taboo" in Britain, partly because not enough is said or written about it.
"People don't know there's a problem. And they don't know that it's something they can have a real impact in changing, should they wish to," she says.
"We definitely need to become less precious about egg and sperm donation. If you're fortunate enough to produce healthy eggs or sperm, you have the ability to make a profound impact on a family's happiness.
"That's a very powerful position to be in and we need people who are brave and kind enough."
Donated sperm or eggs are necessary if a person isn't producing their own, or if they have a high risk of passing on an inherited disease. Donated eggs may also be needed if a woman has had a premature menopause, or has lost the use of her ovaries due to medical problems or cancer treatment.
Morris says: "People who donate want to help other couples, and they can. They usually have a huge sense of pride, and say it's the most wonderful thing they've ever done."
Some clinics may ask donors to go in twice a week for up to four months, although the time that procedures can take is variable.
Donors are asked to abstain from sex and masturbation for between two or three days before donating.
A private room is provided for donors to produce a sperm sample, and the sperm is then treated and stored at the clinic, and inseminated into the recipient woman at her most fertile time.
Egg donation may either be altruistic – when a woman donates purely to help others – or as part of egg sharing, when a woman is having fertility treatment herself, and donates some of her eggs to others.
The donor woman's ovaries may initially need to be suppressed through either daily nasal sprays or injections, for two to four weeks.
The ovaries are then stimulated, usually by self-administered daily injections, for around 10-14 days.
When scans show the woman is ovulating, egg collection is usually performed through the vagina, under either general or local anaesthetic. Up to 16 eggs may be collected per donation cycle.
Usually within hours of eggs being retrieved, the eggs and sperm are treated together in the clinic laboratory, and placed in an incubator. If fertilisation occurs and the embryos are good quality, a maximum of two embryos can be implanted into the recipient woman.
The biggest risk for egg donation is overstimulation of the ovaries, which carries a tiny chance of the ovaries twisting. This can affect fertility, although the risks are minimal.
Some people may choose to arrange sperm donation from someone they know, or through private arrangements other than a clinic.
The NGDT advises them to get legal advice if thinking about this route, to clarify the biological parent's possible legal obligations to any offspring.
If donation is through a licensed clinic, the child has no legal, financial, social or moral rights over their donor.
"The important thing to bear in mind is that there are long-term implications to egg and sperm donation – it's not just the physical here and now of going to the clinic," warns Morris.
In 2005, donor anonymity was banned in the UK, which means that from the age of 18 all donor-conceived children now have the right to know the identity of their genetic parents.
Initially, donor numbers dropped when the anonymity ban was introduced, but they quickly picked up again and are now higher than before the ban.
"The donors I speak to see the removal of anonymity as such a positive thing," says Morris. "They want to be able to be traced if that's what the offspring wants."
As part of the donation process, donors are encouraged to write a goodwill message about why they wanted to donate. This can be passed on to any offspring when they're 18 if they know they were conceived from a donation and want more information about their biological parent.
Morris adds: "It's a very personal, long journey, and potential donors have to be sure that what they're doing is 100% correct for them."
The Human Fertilisation and Embryology Authority (HFEA) is currently examining how to boost donor numbers, and is in the process of completing a public consultation into egg and sperm donation.
An HFEA spokesman explains: "There's clearly a donor shortage, and we wanted to see if any of the things we're doing are creating an artificial barrier to people donating."
The consultation looked at intra-family donation, the number of families a donor can agree to help create, and compensation – which is currently set at up to £250 for loss of earnings, plus reasonable expenses.
He adds: "What we don't want to do with compensation is create an incentive or see a market for egg and sperm donation. It should just be appropriate compensation."
British Fertility Society guidelines state that healthy men aged between 18 and 40 are eligible to donate. However, clinics and individuals have the right to accept donors who are older.
Egg donors must be aged between 18 and 35.
Donors should be free from any serious medical problems and have no history of congenital disease.
About 600 babies are born each year in the UK from donated sperm, and about 450 from donated eggs.
The maximum number of families a donor can help is 10.
The joy donating can bring is exemplified by Laura and David, who have two children thanks to a sperm donor.
They told the NGDT: "Nothing we can say can ever come close to thanking the man who made this possible. For many years we were broken-hearted. Now we have a very happy family.
"Our lives have been totally transformed thanks to our donor. Each night we tuck up our treasured, bright, wonderful little girl and our completely mad, sweet, beloved little boy – because of the generosity of just one man. Thank you."
For more information about egg or sperm donation, and a list of licensed fertility clinics, visit www.ngdt.co.uk, or ring 0845 226 9193.