Unregulated sperm donation is leading to unusual situations in which the children of lesbians are mixing socially — creating a risk of incest.
One of South Australia's foremost experts in reproductive technology - Andrew Dutney - said that in one reported case, about 30 lesbians were impregnated by sperm from one man, the Advertiser reported.
The mothers then organised picnics with all the children, raising the fear they might socialise with their half-siblings without realising they were related.
In another case, a man's sperm was used to produce 29 children, most of whom were living in Adelaide.
They did not know who their half-siblings are, raising concerns that in a "big country town" like Adelaide, they could accidentally commit incest.
In South Australia it has become standard practice to identify sperm donors, which has put men off donating through reproductive clinics.
Fertility treatments do not generally cater to homosexuals, because the law says it is only for infertile couples or those at risk of transmitting a serious defect.
These factors combine to push many people wanting children to seek help elsewhere — either through "turkey basters" or casual sex with friends or willing participants found online.
Dr Dutney, the former chairman of the SA Council on Reproductive Technology and Associate Professor of Theology at Flinders University, said the SA regulations were at fault and should be repealed altogether, leaving reproductive medical units to comply with the national ethical guidelines.
He cited the example of the "very generous" sperm donor to emphasise that when people were excluded from access to reproductive technology, it forced them to go it alone, and have children outside the normal system.
Those children were born about a decade ago, meaning they will be reaching adolescence in the next few years.
"The effect of our regulations here in SA is that they produce unregulated donor conception, whereas a system with a lighter touch would bring a whole lot more parents and children into the light," Assoc Prof Dutney said.
"The situation at the moment is that ... by adhering to the SA legislation, clinics have to be in breach of the national code.
"Under SA's legislation, anonymity is guaranteed while under the national code of ethics, the child's access to knowledge has to be provided."