Professor Valerie Beral of Oxford University said that childbirth and breastfeeding are known to prevent breast cancer.
"Why aren't we thinking of mimicking the effects of childbirth?" Guardian.co.uk quoted, her, as saying.
"We don't know how this happens and nobody is doing research on it. e should be looking at hormone production during late pregnancy and lactation," she added.
During the study, Beral used large amounts of statistical data to identify the traits or behaviour that put women at risk of breast cancer.
She cited the example of cervical cancer, where most cases were found to be caused by the humanpapilloma virus, which led to the development of a vaccine that is now given to schoolgirls aged 12 and 13.
Beral believes that a more interesting candidate for study is prolactin.
"The one hormone that has to do with breast changes doesn't appear until late pregnancy. It goes up exponentially. It produces the changes in the breast that make for lactation," she said.
"Why isn't anyone looking at it?" Whichever hormone or hormones are responsible, short-term exposure during late pregnancy and breast-feeding provides life-long protection, which is exactly what, is required of a vaccine or preventive drug.
But "fewer than a dozen people" are looking in this direction, she said.
"It is not well-funded. It is not mainstream research. Why isn't it a priority of the cancer community?"
She said if somebody made the breakthrough that led to the prevention of breast cancer, it would win a Nobel Prize.