Sperm donors are in hot demand with the shortage of donors the worst it has ever been in New Zealand.
About 450 women are on the waiting list for a donor at Fertility Associates, which has clinics throughout the country, with the wait time sitting at about two years.
At Auckland's Fertility Plus the wait time is just as long and there is an official wait list of about 40 women but scientific director Margaret Merrilees said she believed there were many more women who would put their names forward if there were more donors.
"We are desperately short of donors," she said.
Medical director of Fertility Associates Auckland Simon Kelly said women waiting for donor sperm for IVF treatment could expect to wait about a year while the wait for women wanting sperm to be inserted straight into the uterus to allow for a more natural impregnation was about two years.
He said the shortage was the worst it had ever been despite having seen an increase in donors in recent years.
Single women looking to start a family on their own were behind the growing demand, he said.
"It's a change in society. A lot more women in their mid-to-late 30s are coming in as single women looking for treatment. People are leaving having families until later and that's reflected in the numbers of single women we are seeing."
Kelly said they had noticed a "dramatic" increase in demand from single women during the last four or five years, he said.
"We've always had heterosexual couples and lesbian couples looking for sperm donor treatment but the biggest phenomenal change has been in the number of single women coming."
The long wait time meant the clinic often encouraged women to see if they could find their own personal donor to speed up the process, he said.
Kelly estimated another 200 sperm donors would be needed just to cope with the current demand but said that would involve screening double the number of men to find enough suitable donors.
He said the clinic usually had about 50 donors at any one time. Under New Zealand law donors could provide sperm to up to five families. Since the clinic was set up in 1987 more than 2000 men had donated sperm, he said.
The law in New Zealand also stipulated donors could be compensated for expenses like travel and parking but could not be paid for donating. It was also an open process which meant once the child turned 18 they were able to access their records and get in touch with their biological father.
Kelly said both of those factors made it harder to attract sperm donors.
"We are always amazed how many guys do it from an altruistic point of view."
Merrilees agreed there had been huge growth in the number of single women wanting a donor because it had become more socially acceptable in recent years.
Not only had their demand grown but the number of sperm donors had decreased. She believed that was largely because of the time commitment needed to go through the process but said the requirement for openness also put some off.
Fertility New Zealand spokesperson Juanita Copeland said it was already a difficult time for both couples and single women so being told they could have to wait up to two years could be very stressful.
"I think part of the whole stress around assisted reproduction is waiting. The first thing you are ever told if you visit a fertility clinic is that age is the driver. If you're already 30, to turn up and be told that at 32 your fertility starts to plummet, it's incredibly stressful for people."
She agreed more compensation could potentially attract more sperm donors but said it was a comfort to many recipients to know the donor was doing it purely to help someone else out.
"We would like to see more compensation for donors but not to the level we see overseas because it can quickly become a heavily commercial exercise."
She encouraged more men, particularly those who had finished their own family and knew how special it was, to consider donating.
"It seems like a really simple act but it's a simple act which is massively life-changing for couples. It's making their dream of parenthood come true."
"Best thing in the world"
Becs Carter and Hope Shearer are now the proud parents of a two-week old baby girl. But if it hadn't been for the generosity of a donor, they would never have been able to start their own family.
"It's awesome - the best thing that we've done. The best thing in the world," Carter said.
The women started the process to find a sperm donor about four years ago and Carter gave birth to Frankie James Carter-Shearer two weeks ago.
They were told there was an 18-month to two-year wait for sperm donors when they put their name down for a donor.
"It was really disappointing. You're ready to start your family and get the ball rolling and move on and you just have to sit back and wait. There's literally nothing that you can do about it."
Carter said they were grateful for the generosity of the donor and encouraged other men to consider it too.
"To have someone who was selfless enough to donate so that someone like us could have a family, you can't put that into words," she said. "It's amazing. It's such a gift."
• Men must be between the ages of 20 and 45.
• Donors are required to give a detailed medical history, have a blood test done and provide a sperm sample for testing before being accepted as a donor.
• If accepted another sperm sample is taken, frozen and quarantined for three months before it can be used for treatment.
How to become a donor