Rose Epstein Frisch, an associate professor emerita of population sciences at the Harvard T.H. Chan School of Public Health and a pioneer in elucidating the biological mechanisms of fertility and cancer in women, died January 30, 2015 in Cambridge, Mass.

Frisch’s discovery that the energy stored in body fat governs when a woman becomes fertile led to the discovery of leptin, the hormone that implements this biological pathway. The effect is that a woman’s being too lean, whether from malnutrition or intense exercise, leads to decreased fertility or even infertility. The mechanism, overlooked by demographers and the medical community, has far-reaching implications for policies for alleviating hunger across the world. In related work, Frisch demonstrated the relationship between early athletic activity and later-life cancer.

“Dr. Frisch’s studies were visionary and set in motion a chain of discoveries that led to a much better understanding of women’s health,” said Lisa Berkman, director of the Harvard Center for Population and Development Studies, where Frisch worked for decades. “What also was remarkable was that this was accomplished during a period when most women scientists struggled to have their work recognized.”

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