Several walls of the fertility clinic are adorned with photographs of proud parents and their offspring, a visible reminder for obstetrics and gynaecology associate professor Wayne Gillett of the importance of their work.
He would like to add more photographs to the wall, but with the demand for eggs and sperm outstripping supply, it is a slow process.
In the case of egg donations, waiting times were up to three years, placing further stress on clients, he said.
"This is a hugely growing problem and we have a lot of desperate women out there."
About one in four sperm donors met the clinic's required criteria, and the Otago service needed at least five or six donors to service demand.
Despite advertising for donors, only three or four donations were sourced locally each year, with the service having to go outside the region to meet demand from ethnic clients, Prof Gillett said.
The problem would be exacerbated if it were not for the number of people bringing in their own donors, he said.
"There is no doubt we have a serious donor crisis," he said.
While donor eggs were used by women whose ovaries had stopped working, or who do not have ovaries, more women were delaying childbirth, reducing their chances of pregnancy.
Prof Gillett said more than 10% of women who contacted the service were aged over 40.
"It is a concern that women are delaying childbirth; it places a lot of pressure on them, and I can't see it getting any better."
So far this year, 25 women were waiting for egg donors, and six had been offered eggs, but from that number only three were likely to have a baby.
Two thirds of those who became egg donors were either friends or relatives of the recipient.
These women were usually aged between 21 and 35 with no history of serious inheritable diseases and had ideally completed their own family, he said.
"We would love to have more donors. The people who do so do it for very altruistic reasons."
Opening in 1980, the clinic operated one of the first spermbanks in the country, originally providing a service for the entire South Island.
While the service still operates the spermbank, it began offering its in vitro fertilisation (IVF) programme in 1988, which gives couples experiencing male factor infertility the chance to have a family by using the man's own sperm.
"Donor insemination used to be the commonest reproductive techniques until about 1998, when IVF technology improved so we didn't have to use donor sperm anymore - we could use the man's sperm."
Treatment with donor sperm resulted in pregnancy rates of up to 20% per cycle, he said.
In 1998, with the introduction of the treatment Intra-Cytoplasmic Sperm Injection (ICSI - the direct injection of sperm into an egg) the chance of a successful pregnancy increased to 50% per treatment.
While the ICSI process had revolutionised the management of males with infertility, there was still a need for donor insemination, particularly with increased demand coming from single women and lesbian couples, he said.
"Half of all our donor insemination treatments involve single women or lesbian couples," he said.
There were strict rules governing who could donate sperm and who could apply, a far cry from when the service paid any volunteer $25, he said.
Because of ethical concerns, the clinic now reimbursed people for expenses, and no longer paid people for donations.
The clinic also restricted each donor to four families, to allow two, or sometimes three, children per family.
If the donor belonged to an ethnic group, with relatively few people in the population, the restrictions would be even more stringent, he said.
Concern over consanguinity - people descending from the same person - meant sperm could only be used four times successfully from the same donor.
While clients are not able to see photos of donors, they are able to read extensive profiles, including their medical history.
Men who donate sperm are now required to be identifiable following a law change on August 20, 2005.
Children born after that date, once they turn 18, can now ask the clinic for the identity of the donor.
"We have had children in the past who have wanted to contact the donor, but some men did not want to have a bar of it.
"Now people who are prepared to be donors are prepared to declare who they are, and I am pleased to say New Zealand is leading the world with this policy," he said.