Sperm donors are so in demand there is up to a two-year wait, prompting one woman to fork out thousands of dollars to find one faster.
Karen (not her real name) has placed two newspaper advertisements in the hope of attracting an unknown sperm donor, otherwise the single mother could wait two years before she is eligible to choose one.
The 39-year-old, who wanted to remain anonymous, desperately wants to give her 1-year-old son a sibling but is no longer in a relationship with his father.
She had given years of thought to sperm donation before she met her previous partner and when the relationship ended she decided to pursue the option.
When she was told it could be two years before a donor agreed to his sperm being used by a single woman, she advertised.
"When you get to my age you might only have a year or two when you can have more children, so I could be out there in the dating scene and trying to meet men and all of that is just so unstable for my little son.
"And even if I met the perfect man tomorrow it's going to take a year or two to get to know each other, decide you want to have a child, and then it's almost too late biologically."
The woman, who would also foot the $1500 bill for the donor insemination cycle, said many single women made dedicated mothers.
Karen described herself as a well-educated professional who was able to provide a stable, happy home for another child and had support from her family.
She did not want to ask friends to be sperm donors because "that's a really awkward conversation to have", but she hoped the donor would eventually be known to the child.
So far she had received eight genuine responses through Repromed Auckland, a private fertility clinic, though it is expected not all of them will be able or want to continue the process.
Repromed clinical director Dr Guy Gudex said finding donors in New Zealand, where it is unpaid, had always been difficult and demand for them had increased.
"But it's got even harder over the past 10 or 15 years. One of the reasons is the whole identifiability issue.
"That requirement that you one day might be identifiable might put some people off."
Dr Gudex said a significant amount of sperm donation is for same-sex couples and single women.
"There's just an increasing number of women who either by choice or by circumstance don't have a partner and are getting concerned about age.
"A lot of them approach us in their mid to late 30s and the dilemma with that is donor insemination works best in women under the age of 40."
He said there was at least a 12-month wait and in some cases longer.
Donors can specify who gets their sperm, for example, they may exclude single mothers.
- By Natalie Akoorie of the NZ Herald
