A chart indicating the likelihood of conception linearly declining with age (86% for women aged 20–24, 78% for 25–29, 63% for 30–34, 52% for 35–39, 36% for 40–44, 5% for 45–49, and 0% for 50 and over) is widely used on Internet fertility sites and by medical professionals. Its origin has been unknown until now. Through a literature survey, the author found that two books had contributed to the making of the chart. Among the seven points on the curve, three are based on data that are not the

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... lihood of conception, while four are probably derived from oversimplified description of fecundability estimates for American Hutterite and Taiwanese women in the 1950s and 1960s. At least two professionals are responsible for the fabrication or falsification of data.