A couple who struggled through years of secondary infertility, including seven miscarriages and four rounds of IVF, have developed a new supplement they claim will "turbo charge" men's sperm.
But a leading fertility specialist says Vitamenz is unproven and should be properly tested before being sold to couples trying to conceive.
Aaron and Jacinta Gascoigne fell pregnant with son Jack, now 7, in their early 30s but when the Auckland couple tried for number two they suffered repeated miscarriages.
Their first attempt at in-vitro fertilisation was unsuccessful and the couple were dismayed to find they were producing middle to low-quality embryos.
Tests revealed Mr Gascoigne, now 41, had low motility (slow-moving) sperm. Doctors also discovered Mrs Gascoigne, 37, had a parasitic worm known as bilharzia living inside her for almost a decade, which probably caused the miscarriages.
One pill killed the parasite.
Mr Gascoigne took Menevit, a vitamin already available to aid men's fertility, but two more IVF cycles produced poor quality embryos.
So Mr Gascoigne said he "went on the internet, to the library, talked to the lawn mower man, to blokes at the gym" about what he could do, finally identifying nine key ingredients which he began taking daily.
At the next IVF cycle the couple produced three of the highest grade embryos, one of which became 18-month-old daughter Ava. Mr Gascoigne is now marketing the ingredients as Vitamenz, on his website.
However, reproductive medical specialist and Fertility Associates Hamilton director Dr VP Singh said vitamins' efficacy should be scientifically proven through randomised controlled trials, as new drugs are. "As modern medical practitioners we have to be very careful drawing conclusions from one case."
Dr Singh said Fertility Associates endorsed Menevit for men because a small study in Australia showed it improved IVF results for patients who had ICSI - where the sperm is injected into the egg.
Infertility Solutions International director, naturopath and medical herbalist Brad Crouch said it was possible the supplements improved Mr Gascoigne's fertility but each person's health was unique and they might not be a solution for all men.
* L-Arginine: amino acid supports sperm production
* L-Carnitine: thought to support motility
* Taurine: antioxidant, supports male fertility as well as blood pressure, circulation and mood
* Selenium: needed to properly shape sperm and maintain sperm count
* Zinc: appears to protect sperm from bacteria and damage
* Folic acid: low levels are associated with poor sperm health
* Vitamin E: antioxidant supporting sperm motility
* Vitamin C: protects sperm and its DNA
* Kiwifruit Extract: antioxidant which defends cells from stress.