P was born in 1951. In 1972, she first learned that while she was in utero, her mother had ingested the synthetic drug estrogen diethylstilbestrol (DES) for the prevention of miscarriage. P was told in 1972 that DES daughters could suffer injuries. P went to a DES clinic at the UCLA Medical Center and was diagnosed as having adenosis, a precancerous condition that required careful monitoring. In 1976, she had an abnormal pap smear and underwent a dilation and curettage, a surgical procedure to remove abnormal tissue. In 1978, P underwent a complete hysterectomy and a partial vaginectomy in order to remove malignancy. Starting in 1972, P attempted to discover the manufacturer of the DES ingested by her mother. Efforts increased as her condition became more acute. The doctor who prescribed was dead, and no one else had any records as DES was a fungible drug. In 1978, P was aware of the pendency of one or more DES suits alleging that DES manufacturers were liable to those injured due to their failure to test or failure to warn. As of 1978, there was no conclusive evidence in the record to show that a reasonable investigation would have disclosed specific proven facts that would establish any wrongful conduct on the part of a DES drug manufacturer. In March 1980, Sindell v. Abbott Laboratories was decided. P could state a cause of action against the DES manufacturers of a substantial percentage of the market share of the drug. Almost one year after Sindell, P brought this action. Ds moved for summary judgment, in that section 340, subdivision (3), set forth a one-year statute of limitations period. P denied that the suit was time-barred. P asserted that the statute did not commence until she learned of the Sindell decision, because only then did she realize that she would be able to successfully bring her claim. The court granted D's motion. The court of appeals reversed, and D appealed.