Women given the drug DES until the mid-1970's had a high risk of breast cancer and their daughters had a high rates of miscarriage or infertility.

And sons of women who took DES were likely to be born with undescended testes, a condition known to be linked to testicular cancer.

Now, the grandchildren of DES recipients are being monitored amid fears they could have serious problems.

Melbourne Royal Women's Hospital chief gynaecologist Ross Pagana has likened the DES tragedy to that of the thalidomide scandal of the 1950's in which the pregnancy drug caused birth defects.

Unlike DES victims in the America, Australians were unlikely to be able to sue because of problems proving exposure to the drug.

Dr Pagano warned that 300,000 Australian men and women were exposed to DES faced uncertain futures and a lifetime of monitoring.

"I am too scared to say there won't be more problems because we just don't know," he said.

Dr Pagano, head of the hospital's DES Clinic, collaborates with a counterpart in the United States where tests and studies on DES patients are also under way.

DES, also known as stilboestrol and diethylstilboestrol, was prescribed to thousands of Australians between 1940 and 1971.

It was a synthetic oestrogen injected or ingested as a pill and was given to pregnant women to prevent miscarriage and bleeding.

It was also used to treat height problems in children who were either excessively short or tall. They were urged to a discontinue its use after a report in the New England Journal of Medicine in 1971 blamed it for an extremely rare form of vaginal cancer in the teenage daughters of DES users.

Previously only ever known in elderly women, the aggressive vaginal tumors were usually a death sentence without radical hysterectomy and vaginectomy.

"The medical profession realised it faced a potential disaster after that 1971 diagnosis," Dr Pagano said.

Thile the incidence of the cancer was relatively rare, Dr Pagano said most girls born to DES mothers were later found to suffer genital and cervial abnormalities leading to fertility problems.

They were found to have a five-times higher risk of ectopic pregnancy than normal and three times more likely to miscarry or have premature births.

DES was banned as a fattening aid for poultry in 1959 after side effects included breast growth in men who ate chicken meat.