Some 20 per cent of IVF rounds in 2020 were due to an infertile man, with another 11.2 per cent due to both a man and woman being infertile within a couple, the Assisted Reproductive Technology in Australia and New Zealand 2020 report from UNSW found.

When looking for an underlying cause, three-quarters of infertile males were left undiagnosed.

"(That) reflects our lack of understanding of the reasons for poor semen quality," Fertility Society of Australia and New Zealand president Luk Rombauts said.

Another seven per cent were attributed to previous vasectomies and 2.4 per cent had turned to IVF after receiving treatment for cancer.

Fertility research previously focused solely on women, despite men playing an equal part in conceiving a baby, Prof Rombauts said.

As more data was collected on the causes of male infertility, scientists stood a better chance of understanding its impact, he said.

The results show more research and education are needed and it's likely genetic studies could reveal risk factors for sterility.

Overall, 96,000 IVF cycles were performed in Australia and New Zealand in 2020, resulting in 18,462 new babies.

That's a 7.6 per cent increase since 2019 and means one in 18 babies born in 2020 in Australia were conceived using IVF.

The COVID-19 pandemic may have had a dampening effect on the number of births, as health restrictions led to IVF being limited in some states, UNSW public health researcher Professor Georgina Chambers said.

Same-sex couples and single women accounted for 14 per cent of cycles in 2020.

Genetic testing, which allows parents to test embryos for chromosomal errors and genetic diseases, was used by about one in 10 IVF cycles in 2020.

Australian Associated Press