A storm has erupted over the pregnancy of an eight-year-old Asian elephant at Sydney's Taronga Zoo, with three animal welfare groups claiming the female is too young to breed.
The animal is the first elephant to become pregnant while in captivity in Australia.
But the RSPCA, Humane Society International and International Fund for Animal Welfare said elephants should be at least 11 years old before breeding under an approved captive management plan.
"Allowing an eight-year-old elephant to conceive is the equivalent of allowing your 12-year-old daughter to become pregnant; it is completely irresponsible and we want to know why this was allowed to happen," International Fund for Animal Welfare's Asia-Pacific director Erica Martin said.
Taronga Zoo said the 11-year reference in the plan related only to the earliest age of conception in American zoos, while European zoos had elephants pregnant as young as five.
Taronga spokesman Mark Williams said: "This was not an accident, it was carefully planned and it was done based on the recommendations of international experts in elephant reproductive biology who assessed all four of our animals as reproductively viable.
"This has come about based on pure science, not emotion, and … it seems to be a misinterpretation by these groups," he said.
But RSPCA chief scientist Bidda Jones said the pregnancy was extremely risky and had no conservation value.
"Essentially the young female is the zoo's very own cash cow," Dr Jones said.
Taronga and Melbourne zoos controversially imported eight Asian elephants from Thailand in 2006.
Taronga Zoo said the pregnancy was a breakthrough in a conservation effort for the dwindling species and showed the Thai elephants had adapted happily to their new home.